CURRENT RESEARCH

We perform lots of research both in experimental and theoretical chemistry driven by up-to-date needs. We develop brand new mathematical methods and apply them to solve real-world problems in molecular biology and molecular physics, beyond chemistry. We do chemical syntheses of functional materials, physicochemical experiments in nanochemistry and nanomaterials, research in electrochemistry, and energy-storage devices. 

Semiempirical Molecular Dynamics

Electronic-structure-based simulations molecular dynamics (MD) simulations are normally based on pure density functional theory (DFT), such as the PBE functional. These can be used to reveal either nuclear (less often) or electronic (more often) phenomena. The usage of the electronic structure methods as gear for Newtonian MD allows one to avoid parameterization of the covalent and non-covalent atom-atom interactions in a simulated system. There are systems for which adequate parameterization requires the implementation of specific functional terms. Therefore, coupling of the electronic-structure-based Hamiltonians deems fruitful. The principal problem of DFT-based MD is the available time scale. 10-100 ps of the real-time nuclear motion is frequently not enough to observe substantial nuclear displacements and satisfy sampling requirements (see the ergodic hypothesis). We develop semiempirical molecular dynamics PM7-MD which can simulate much longer periods of nuclear motion. Even though accuracy-related concerns are always a cornerstone in any simulation, numerous many-component systems were described properly using PM7-MD. You may find abundant examples in our publications starting in 2014.

Potential Energy Landscapes

The potential energy landscape, also referred to as the potential energy surface, is a mathematical concept that mathematical chemists use to describe all possible states of the nuclear-electronic system. The processes occurring in a given molecular system can be associated with energy alterations (thermodynamics) and energetic barriers (kinetics). The energetic effects represent functions of the model Hamiltonian. All principally possible atom-based processes can be explored, irrespective of whether they are spontaneous or forcible. We develop methods to precisely and efficiently sample the potential energy landscape to derive meaningful physical insights and rationalize real-world observations. The methods are time-independent, therefore, they do not suffer from the limitations of small time steps and alike. The methods are temperature-independent. Consequently, the entropic effects can be isolated and studied independently. The deliberate and conjugated application of various levels of quantum theory allows one to explore the coveted energy landscapes at an unprecedented pace and outstanding accuracy.

Classical Molecular Dynamics

The idea of using Newtonian equations of motion to mimic atomic and molecular thermal motions is certainly one of the most brilliant achievements of humanity ever. We designate it classical because the atomic nuclei travel as any macroscopic mechanical body. As long as the integration time step is smaller than 2 femtoseconds, such a model performs quite decently. The atomic nuclei steadily populate the phase space by preserving the temperature, pressure, or inherent energy of a system. The effect of electrons is incorporated into the effect of the corresponding nucleus. The intermolecular and intramolecular interactions are mimicked via simple equations which can be non-iteratively and computationally efficiently solved. We have developed over a dozen Hamiltonians to perform molecular dynamics simulations of a very wide range of compounds, materials, interfaces, liquid phases, and processes. The models extensively account for the data obtained from practical quantum chemical studies and physicochemical experiments.

Reactive Molecular Dynamics

Being able to observe chemical reactions in real time would heavily boost the progress of chemistry. The practically important developments in chemical technologies can become uncomparably faster than today if researchers get tools to directly palpate the elementary processes in their test tubes. The problem is that chemistry is done by the electrons. Those, one by one, are too poorly described by the classical equations of physics. The idea beyond reactive MD is to mimic the chemical behavior of electrons via the corresponding potential energy surface. The energy of the simulated system is described by rather sophisticated mathematical functions. The parameterization of such functions is performed by using quantum chemical data. The major advantage of reactive molecular dynamics is the absence of the system’s wave function and, therefore, no necessity to iteratively solve it. As a result, the simulations of significantly large chemical systems become possible. Analogously, the available time frames become much larger than with any quantum chemistry-empowered method. We have a long record of the fulfilled reactive dynamics simulations, development, and refinement of the Hamiltonians to describe the problems in which the real-time dynamics of the reacting species is desirable. The simulations of the nanoscale carbons, insulating polymers, high-energy compounds, and catalytic processes are bright examples of how creatively reactive MD can be employed. The so-called buckybomb as a vicious weapon against little bastards has been created by Vitaly Chaban and highlighted by media throughout the globe.

Perturbations via Injections of Kinetic Energy

Isomers are omnipresent in chemistry. There are enough examples in textbooks illustrating how the isomers make a difference in all respects of the elementary process including numerous life-related phenomena. Being one of the most difficult and enigmatic themes for chemistry students,  the isomers cannot be distinguished via elemental and quantitative analyses but differ according to their potential energies. The term isomer may equally apply to a state of a single molecule and a state of a macromolecular ensemble. The stationary points populating the potential energy landscape correspond to multiple isomers and transitions among them in the simulated system. We have developed and fruitfully applied the energy injection method to identify the isomers in the systems of sophisticated chemical compositions. An arbitrary portion of kinetic energy is periodically injected into the system that evolves according to the Born-Oppenheimer dynamics. The external energy perturbs the geometry of the system making it change its evolution over the potential energy surface. The system is, next, allowed to accommodate the excess kinetic energy. Ultimately, the resulting conformation is saved and processed via the local optimization techniques, whereas the system continues traveling over the phase space. The method allows one to identify and systemize manifold stationary states which are, otherwise, inaccessible for sampling. We have demonstrated perfect results while treating nanoscale clusters, many-component mixtures, chemical reactions featuring high activation barriers, quantum dots, coordination chemistry, etc.

Chemical Reaction Coordinates

In principle, ab initio molecular dynamics can simulate chemical reactions by sampling the part of the phase space around the reaction event. However, the problem is technical. The maximum realistic length of the AIMD simulation can hardly exceed 100 ps, whereas the chemical reactions take place over way longer times. One of the plausible solutions is to identify a so-called reaction coordinate and sample the corresponding fraction of the energy landscape forcibly. This trick is reminiscent of steered MD and the potential of mean force calculations in other fields of computational chemistry. The absolute majority of chemical reactions can be described either through a single coordinate or as consequently scanned simple coordinates. Some rare reactions represent multi-dimensional processes though. By sampling the reaction coordinates, we obtain a wealth of chemical information that allows us to characterize the feasibility of hypothetical chemical phenomena. The major outputs in such studies are thermodynamics potential changes, charge density redistributions, and continuously altering nuclear geometries during the course of the propagated chemical reaction. 

Optimizing Carbon Dioxide Scavengers

The capture of carbon dioxide (CO2) using novel sorbents is a promising technology for reducing greenhouse gas emissions from industrial and power generation processes. Novel sorbents are materials that have been specifically designed or modified to have a high affinity for CO2. They can be used to capture CO2 from flue gas or other gas streams, and then release it in a concentrated form for storage or utilization. Metal-organic frameworks (MOFs) are a class of highly porous materials with a large surface area. This makes them ideal for adsorbing CO2. MOFs can be tailored to have specific properties, such as a high affinity for CO2 at low temperatures or pressure. Ionic liquids are molten salts that have a liquid-like consistency at room temperature. They can dissolve CO2 very well, and they can be tuned to have specific properties, such as a high capacity for CO2 or a low volatility. Amines are organic compounds that have a high affinity for CO2. Amine-modified sorbents are materials that have been coated or impregnated with amines. This makes them effective for adsorbing CO2 from flue gas and other gas streams. Novel sorbents offer several advantages over traditional CO2 capture technologies, such as amine scrubbing. They can be more efficient and less energy-intensive, and they can be used to capture CO2 from a wider range of gas streams. However, novel sorbents are still under development, and they need to be scaled up and commercialized before they can be widely deployed.

Enhancing Electrolyte Systems

Electrolyte systems based on ionic liquids (ILs) are a promising new class of electrolytes for energy storage devices, such as batteries and supercapacitors. ILs are salts that are liquid at room temperature, and they have a number of properties that make them attractive for use in electrolytes, including (1) high thermal stability, (2) wide electrochemical window, (3) non-flammability, (4) good ionic conductivity, (5) tunable properties. ILs can be used to create electrolyte systems with a variety of properties, depending on the specific application. For example, ILs can be used to create electrolytes with high ionic conductivity and a wide electrochemical window, which are ideal for use in lithium-ion batteries. ILs can also be used to create electrolytes with high thermal stability and non-flammability, which are ideal for use in high-temperature batteries.

Some of the most promising IL-based electrolyte systems for energy storage devices include lithium-ion batteries: ILs can be used to create high-performance lithium-ion battery electrolytes with a wide electrochemical window and high ionic conductivity. IL-based electrolytes can also improve the safety and performance of lithium-ion batteries by reducing the risk of thermal runaway and extending the cycle life. ILs can be used to create electrolytes for sodium-ion batteries. Sodium-ion batteries are a promising alternative to lithium-ion batteries because sodium is a more abundant and less expensive element than lithium. IL-based electrolytes can improve the performance of sodium-ion batteries by increasing the ionic conductivity and reducing the viscosity of the electrolyte. ILs can be used to create electrolytes for supercapacitors. Supercapacitors are energy storage devices that can charge and discharge quickly, making them ideal for use in hybrid and electric vehicles. IL-based electrolytes can improve the performance of supercapacitors by increasing the ionic conductivity and widening the electrochemical window.

Ionic liquid-based electrolyte systems have the potential to revolutionize the energy storage industry. By improving the performance, safety, and cost of energy storage devices, IL-based electrolytes could enable a wider range of renewable energy applications and help to reduce our reliance on fossil fuels.

Nanoscale Molecules

Nanoscale molecules are molecules that have one or more dimensions that are less than 100 nanometers in size. Such molecules substantially exceed the sizes of conventional molecules. In turn, nanoscale molecules are incredibly small compared to the macroscale world. For instance, a single human hair is about 80,000-100,000 nanometers in diameter. Nanoscale molecules have unique properties that are different from those of larger molecules. For example, they can have a higher surface area-to-volume ratio, which makes them more reactive. They can also have quantum effects, which are unique to the nanoscale. Nanoscale molecules are used in a wide variety of applications, including (1) medicine (to deliver drugs to specific cells or tissues, or to create new types of medical implants); (2) electronics (to create new types of electronic devices, such as transistors and solar cells); materials science (to create new types of materials with unique properties, such as strength, lightness, and conductivity).

Fullerenes are carbon molecules that have cage-like structures. The smallest fullerenes are about one nanometer in diameter and have unique properties that make them useful in a variety of applications. The fullerenes can grow pretty large and contain 720 carbon atoms and probably way more. Carbon nanotubes are carbon molecules that have cylindrical structures. The smallest nanotubes can boast about one nanometer in diameter. They exhibit a very high strength-to-weight ratio. The carbon nanotubes can also be significantly wider and contain a few carbon layers. Those are referred to as walls, see multi-walled carbon nanotubes in our publications. Graphene is a single layer of carbon atoms that is arranged in a hexagonal lattice. The ideal structure of graphene is the thinnest and strongest material known to science. Nanoscale molecules are a rapidly growing field of research with a wide range of potential applications. As we explore the unique properties of nanoscale molecules, we are developing innovative ways to use them to improve lives. Professor Vitaly V. Chaban develops and employs quantum chemical and empirical-potential-based methods to find accurate descriptors that characterize novel nanotechnological objects thermodynamically and kinetically.

The Fascinating Chemistry of Phosphonium Ylides

A phosphonium ylide is a type of zwitterion, which represents a molecule with both a positive charge and a negative charge within a single chemical entity. The positive charge is carried by the phosphorus atom, while the negative charge is carried by the alpha-carbon atom. Phosphonium ylides are typically prepared by deprotonating this or that phosphonium salt. The phosphonium ylides are important intermediates in organic synthesis. They are used in a variety of reactions, including the Wittig reaction, the Staudinger reaction, and the Horner-Wadsworth-Emmons reaction. These reactions are necessary routes to synthesize a variety of organic compounds, including alkenes, alkynes, and cyclic ketones. The phosphonium ylides are unusual catalysts. For example, they can be used to catalyze the addition of nucleophiles to carbonyl compounds. This is a useful reaction for synthesizing alcohols and amines. The phosphonium ylides are easy to prepare, kinetically stable, and can be stored for long periods of time. The chemical action of the phosphonium ylides is reasonably selective allowing one to obtain good yields of the coveted products.

The ability of the phosphonium ylides to attract nucleophilic agents made it possible for us to employ the phosphonium-based ionic liquids to act as efficient CO2 scavengers. The phosphonium ylides represent intermediates in the developed and rationalized CO2 scavenging technology. The comprehensive scanning of the reaction energy profiles plays a paramount role in conducting such a sort of research.

In-Silico Corrosion Research

Corrosion protection studies represent a vital aspect of materials science and engineering. They help to extend the lifespan of structures and components exposed to corrosive environments. Corrosion is a natural process that occurs when a metal reacts with its surroundings, leading to the deterioration of the metal surface. Corrosion can cause significant damage to infrastructure, machinery, and other assets. As a result, costly repairs and replacements are necessary at some points. In sustainable technologies, corrosion-related issues must be combated. Some different corrosion protection methods can be used to mitigate the effects of corrosion. These methods can be broadly classified as active and passive protections. Active protection methods involve the application of an external electrical current to the metal surface to prevent corrosion. This is typically done by using an anode, which represents a more reactive metal compared to the protected  metal. The sacrificial anode corrodes preferentially, thereby protecting the other metal. Another common active protection method is impressed current cathodic protection. It involves an external power source to apply a direct current to the metal surface. 

Passive protection methods involve creating a barrier between the metal surface and the corrosive environment. This can be done by applying a coating to the metal surface, such as paint, epoxy, zinc, or an arbitrary sorbent that binds the aggressive corrosion-causing molecules. The metal surface can furthermore be modified by creating a passive film, such as an oxide layer (recall Al2O3), on the surface.

The choice of corrosion protection method depends on a number of factors, including the type of metal, the corrosive environment, and the desired level of protection. In some cases, a combination of active and passive protection methods may be used. Corrosion protection studies are subject to research, as new materials and technologies are constantly being developed. Our studies are essential for ensuring the long-term integrity of structures and components exposed to corrosive environments. Corrosion protection studies play a vital role in several industries, including the oil and gas industry, chemical industry, power generation, construction and transportation industries. Professor Vitaly V. Chaban, affiliates, and international collaborators made a substantial impact on the development of passive protection technologies by simultaneously applying experimental studies and computational modeling in chemistry. In particular, PM7-MD and reaction coordinate scanning methods were employed to rate the corrosion-protecting agents.

Non-Newtonian Fluids

In the realm of fluid mechanics, non-Newtonian fluids stand as a fascinating and complex class of substances that deviate from the conventional behavior of [Newtonian] fluids. Unlike their Newtonian counterparts, whose viscosity remains constant under varying shear rates, non-Newtonian fluids exhibit a dynamic viscosity that responds to external forces. This intriguing property leads to fascinating fundamental phenomena and practical applications.

Non-Newtonian fluids are defined as fluids that do not adhere to Newton's law of viscosity. The latter states that the viscosity of a fluid is directly proportional to the shear rate. In simpler terms, Newtonian fluids exhibit a constant resistance to flow, regardless of the applied stress. Conrariwise, non-Newtonian fluids exhibit a viscosity that changes with the applied shear rate. This sort of behavior can be classified into two main categories:

(1) Shear-thinning fluids. These fluids exhibit a decrease in viscosity with an increasing shear rate. See ketchup, honey, and oobleck (a mixture of cornstarch and water).

(2) Shear-thickening fluids. These fluids exhibit an increase in viscosity with increasing shear rate. See cornstarch and water mixtures and quicksand.

Beyond the primary categorization of shear-thinning and shear-thickening fluids, there exist other types of non-Newtonian fluids with unique properties: (1) time-dependent fluids (kinds of toothpaste); dilatant fluids (cornstarch dissolved in water; (3) pseudo-plastic fluids (kinds of ketchup).

The study of non-Newtonian fluids represents an active area, with ongoing efforts to understand their complex behavior and develop novel applications. Dr. Chaban and coworkers use large-scale classical molecular dynamics (CMD) simulations to unravel the molecular mechanisms underlying the viscosity changes in non-Newtonian fluids. These advances help to develop new techniques for precisely controlling and manipulating the rheological properties of non-Newtonian fluids and expand the range of applications in various fields, including medicine, engineering, and even food science.

 Development of Machine Learning Potentials 

The understanding of the molecular behaviors in condensed-phase systems relies on complex and computationally expensive calculations employing the iterative methods belonging to quantum chemistry. In the world of machine learning, things are expected to get both faster and more accessible. With wisely trained machine learning potentials, chemists can explore the world of molecules at a dramatically accelerated pace. Imagine such potentials as clever algorithms trained on vast datasets of molecules and their microscopic properties. The machine learning potentials learn the intricate relationships between a molecule's structure and its energy. Essentially, we can say that we automatically build maps of potential energy surfaces. While having a full map, the simulations predict the energy of a molecule in virtually any configuration. This practice cancels the necessity to run lengthy quantum calculations. You also do not need huge systems to parameterize your functions.

What one requires to start investigating chemistry is a sophisticated algorithm that has analyzed countless similar landscapes (read similar molecular structures). Machine learning potentials tend to be way faster as compared to the wave function-based computational approaches. Quicker simulations open the door to simulate larger systems and previously inaccessible phenomena. The machine learning intramolecular and intermolecular potentials are probably not as accurate as density functional theory, nonetheless, the average accuracy is sufficient for many realistic applications. Careful validations and chermical intuition are two cornerstone supplements, which empower the machine-learning methods.

The reduced computational demands offered by the machine-learning potentials allow one to redistribute valuable computational facilities among ongoing tasks to accelerate research and development. Sometimes, the machine-learning potentials can identify hidden patterns and relationships in large datasets. This sort of help leads to unexpected insights and potentially groundbreaking discoveries. Most importantly, the approach of substituting the wave function with the potentials eliminates the iterative solutions and dramatically improves scaling. 

Simulating Deep Eutectic Solvents

The ability to tailor the properties of DESs by selecting different combinations of hydrogen bond acceptors and hydrogen bond donors is a significant advantage. This flexibility allows for the design of DESs with specific properties, such as viscosity, polarity, and conductivity, to suit the requirements of a particular application. For instance, DESs with high ionic conductivity are desirable for electrochemical applications, while DESs with low viscosity are preferred for applications involving mass transfer. Shear viscosity and ionic conductivity can be simulated in silico using classical molecular dynamics simulations for the system whose size exceeds the macroscopic limit. 

Furthermore, DESs exhibit excellent solvent properties for a wide range of both polar and nonpolar compounds. They can dissolve various organic and inorganic substances, including metal salts, sugars, amino acids, and polymers. This versatility makes DESs suitable for applications such as extraction, absorption, separation, and purification processes. We simulated the absorption of carbon dioxide (CO2) and hydrogen sulfide (H2S) in menthol-based DESs in the constant temperature constant-pressure (NVT) ensemble. The cell deminsion is extended and the gas phase is added. Such research makes sense to develop materials for natural gas sweetening.

In addition to their unique physicochemical properties, DESs offer several advantages in terms of sustainability and cost-effectiveness. They are typically prepared from readily available, inexpensive, and biodegradable components. Many DESs are also non-toxic and non-flammable, making them safer alternatives to conventional organic solvents. Some researchers argue that DESs as a group of substances display essential advantages over room-temperature ionic liquids as a group of substances.

The growing interest in DESs has led to extensive research efforts focused on understanding their fundamental properties and exploring their potential applications. Our ongoing studies with various research groups worldwide are aimed at developing new DES formulations, improving their performance, and expanding their use in emerging fields such as nanotechnology and biomedicine. The role of hydrogen bonding in DESs can be efficiently unraveled using the in-house methods, such as the kinetic energy injection method.

Design of Materials for Dielectric Capacitors

Dielectric capacitors are fundamental components in electronic circuits, serving as energy storage devices and enabling various functionalities, such as filtering, coupling, and decoupling. The performance of a dielectric capacitor is critically dependent on the properties of the dielectric material used. The dielectric material is usually a carbon-based polymer, such as PP, PET, PC, or PPS. The design of materials for dielectric capacitors plays a crucial role in optimizing their performance characteristics. Prof. VV Chaban and coworkers use a variety of computational and experimental methods to propose better solutions for the novel materials to reinforce dielectric capacitors and, particularly, their resistance to electrical breakdowns.   

A high dielectric constant enables the capacitor to store a larger amount of charge at a given voltage, leading to higher capacitance values. Dielectric loss refers to the dissipation of energy within the dielectric material when an alternating electric field is applied. Minimizing dielectric loss is essential for efficient capacitor operation, particularly at high frequencies. Breakdown strength represents the maximum electric field that the dielectric material can withstand before it undergoes electrical breakdown. A high breakdown strength ensures the capacitor's reliability and prevents catastrophic failure. The dielectric properties of the material should exhibit minimal variation over the operating temperature range to maintain consistent capacitor performance. The dielectric material should be resistant to chemical degradation and mechanical stress to ensure long-term stability and durability. To meet the stated requirements, a wide range of dielectric materials are employed in capacitor fabrication, each with its own advantages and limitations. 

Ceramic dielectrics, such as barium titanate (BaTiO3) and related compounds, offer high dielectric constants and are widely used in capacitors for various applications. Polymer films, such as polypropylene and polyethylene terephthalate, provide good dielectric properties, flexibility, and ease of processing, making them suitable for film capacitors. Electrolytic capacitors utilize a thin oxide layer formed on a metal foil (e.g., aluminum or tantalum) as the dielectric. These dielectric capacitors offer high capacitance values but are typically polarized and have limited frequency response. Mica is a naturally occurring mineral with excellent dielectric properties, including low dielectric loss and high breakdown strength. It is often used in high-frequency and high-voltage applications.

The choice of dielectric material depends on the specific requirements of the capacitor application, considering factors such as capacitance value, voltage rating, frequency range, operating temperature, and cost. In addition to the selection of the dielectric material, the design of materials for dielectric capacitors also involves optimizing the microstructure and processing techniques to enhance their performance characteristics. For instance, controlling the grain size and morphology in ceramic dielectrics can significantly influence their dielectric constant and breakdown strength. Similarly, the thickness and uniformity of polymer films are crucial for achieving high capacitance values and low leakage currents.

Advancements in materials science and nanotechnology have led to the development of novel dielectric materials with improved properties. For example, high-k dielectrics, such as hafnium oxide and zirconium oxide, are being explored for their potential to increase capacitance density in microelectronic devices. Furthermore, the incorporation of nanomaterials, such as carbon nanotubes and graphene, into dielectric composites has shown promising results in enhancing their dielectric properties and mechanical strength. Our ongoing research and development efforts in the field of dielectric materials are focused on addressing the challenges of increasing capacitance density, reducing dielectric loss, and improving temperature stability. These advancements will enable the design of next-generation dielectric capacitors with enhanced performance characteristics, contributing to the miniaturization and improved functionality of electronic devices. Using reactive molecular dynamics, global minimum exproration using kinetic energy injection, and plane-wave DFT calculations contribute to our in-house research program addressing the persisting issues related to dielectric capacitors.

Self-Healing Phenomenon 

Dielectric capacitors are essential components in modern electronics, enabling energy storage, filtering, and voltage regulation in various applications. However, they are susceptible to electrical breakdown, a phenomenon that can lead to catastrophic failure and compromise circuit functionality. Self-healing mechanisms offer a robust solution to mitigate the effects of breakdown, allowing capacitors to recover their insulating properties and continue operating. The chemical products generated during the decomposition of the dielectric material upon electrical breakdown play a crucial role in the self-healing process, influencing the dynamics of vaporization, arc quenching, and insulation recovery. Under the guidance of Prof. Vitaly Chaban, coworkers and collaborators explore the intricate relationship between self-healing in dielectric capacitors and the decomposition chemical products emerged upon electrical breakdown, delving into their formation, properties, and impact on capacitor performance and reliability.

Electrical breakdown in a dielectric capacitor occurs when the electric field strength across the dielectric material exceeds its breakdown strength. This instrumental nuisance leads to the formation of a conductive channel through the dielectric, resulting in a sudden surge of current. The current surge generates an arc, a high-temperature plasma discharge that can cause localized damage to the dielectric material and the electrodes.

Self-healing mechanisms in dielectric capacitors offer a remarkable solution to this challenge. When a breakdown occurs, the intense heat generated by the arc causes the metallization layer in the vicinity of the breakdown to vaporize rapidly. This vaporization, coupled with the decomposition of the dielectric material, creates a high-pressure gas that expands and pushes the molten metal away from the breakdown site, effectively isolating the fault and restoring the insulation properties of the dielectric.

The chemical products generated during the decomposition of the dielectric material upon electrical breakdown play a crucial role in the self-healing process. These products, in solid and gaseous forms, contribute to various aspects of self-healing. We the solid-phase decomposition products a soot. This is usually carbon-rich amorphou mass containing a specific amount of metal. In turn, our collaborators in the lab use the term "metalized layer" to desribe what they observe at the macroscale.  

The decomposition products contribute significantly to the gas pressure buildup that drives the expulsion of molten metal and the formation of the insulating zone. The amount and type of gas generated depend on the chemical composition of the dielectric material and the conditions of the breakdown. Some decomposition products can act as arc quenching agents, promoting the deionization of the plasma and suppressing the arc's propagation. This helps to minimize the damage to the dielectric material and facilitates faster self-healing. The chemical nature of the decomposition products can influence the dielectric properties of the insulating zone formed after self-healing. Some products may contribute to the formation of a stable and high-dielectric-strength insulating layer, while others may lead to degradation or instability over time.

Several factors can influence the type and amount of decomposition products generated during electrical breakdown. The chemical composition of the dielectric material is the primary determinant of the decomposition products. Different materials produce different gaseous byproducts, each with its own set of properties and effects on self-healing. The energy dissipated during the breakdown event influences the extent of decomposition and the amount of gas generated. Higher energy breakdowns typically lead to more extensive decomposition and a greater variety of chemical products. The temperature and pressure conditions during breakdown can affect the chemical reactions involved in the decomposition process, influencing the type and amount of products formed.

Understanding the properties of the decomposition products is crucial for optimizing the self-healing process and ensuring long-term capacitor reliability. Key properties include thermal conductivity, dielectric strength, and chemical reactivity.

The thermal conductivity of the gas affects the rate of heat dissipation from the arc and the surrounding dielectric material, influencing the arc quenching process and the extent of damage. Dielectric Strength: The dielectric strength of the gas determines the ability of the insulating zone to withstand the electric field after self-healing, preventing re-ignition of the arc and ensuring long-term stability. The chemical reactivity of the decomposition products can affect the long-term stability of the capacitor, as some products may react with the dielectric material or the electrodes, leading to degradation or corrosion.

Experimentalists employ various analytical techniques to identify and characterize the decomposition products generated during electrical breakdown. Gas Chromatography-Mass Spectrometry, GC-MS, can be used to separate, identify, and quantify the different gaseous byproducts, providing insights into the chemical reactions involved in the self-healing process. Fourier Transform Infrared Spectroscopy, FTIR, can be used to identify the functional groups present in the decomposition products, providing information about their chemical structure and potential reactivity. X-ray Photoelectron Spectroscopy, XPS, can be used to analyze the elemental composition and chemical states of the decomposition products, providing insights into their origin and potential interactions with the capacitor components. The slightly modified kinetic energy injection method is handy in determining the most probable decomposition products formed after the electrical breakdown in dielectric capacitors.

The field of self-healing capacitor technology is constantly evolving, with researchers exploring new materials, mechanisms, and applications. Researchers are developing new dielectric materials that decompose into beneficial gaseous byproducts, promoting efficient self-healing and enhancing capacitor reliability. Techniques are being developed to control the decomposition process and selectively generate desired chemical products, optimizing the self-healing process and minimizing unwanted side effects. Scavenging layers can be incorporated into the capacitor structure to absorb or neutralize harmful decomposition products, preventing long-term degradation and enhancing capacitor lifespan.