Welcome!
We exploit new advances combining mass spectrometry and laser spectroscopy to access interesting molecular properties that are often hidden in ambient or bulk measurements.
We intend to use this capability to advance problems in atmospheric chemistry, catalysis, nanoscience, gas phase reaction dynamics, and fundamental physical chemistry. Our work is supported by the following organizations:
Apologies for the mess, Google Sites forced us on to the new system and we are still navigating the transition.
News
June 2024
Nicoline's paper, "Photochemical Mechanisms in Atmospherically-Relevant Iodine Oxide Clusters," is accepted at J. Phys. Chem Lett.! She shows that newly formed iodine oxide particles likely undergo complex photochemistry that alters their chemistry as they grow and age.
May 2024
Anna's first paper, Stability and Structure of Potentially Atmospherically Relevant Glycine Ammonium Bisulfate Clusters, is out at J. Phys. Chem. A! This work, a close collaboration with Conor Bready and George Shields at Furman, digs into the structures and stability of hypothesized glycine-containing new atmospheric particles, showing that glycine is surprisingly strongly bound in the particles, potentially leading to its enrichment as particles age.
April 2024
Chris receives the 2024 Godfrey Excellence in Teaching Award!
February 2024
Chris presents a talk at the Molecular and Ionic Clusters Gordon Conference on new results concerning the photochemistry of newly-formed iodine oxide particles in the atmosphere.
October 2023
Congratulations to Hanna Morales Hernandez, who defended her thesis!
September 2023
Chris wins the Stony Brook Foundation Discovery Prize! This on-campus competition is held every two years, and provides $200,000 in funding to pursue high-risk, high-reward basic research. We will be working on a new instrument to simultaneously measure the mass and vibrational spectra of single nanoparticles, with a focus on understanding how chemistry impacts cloud formation.
July 2023
Two nice papers out in one week! One is a study of the chemical nature of the (formal) hydride on a prototypical gold nanocluster, in Angewandte Chemie. Here we show that the H atom actually behaves as a moderately strong acid, suggesting it is relatively protic and may play this role in reactions catalyzed by gold nanoclusters. Thanks to Rebecca Gieseking for the theory help on this, and congratulations to Hanna Morales Hernandez on her first first-author paper!
The other is a collaborative effort in JACS with Eszter Boros's group, where we tried to help understand the mechanism for an intramolecular reaction that releases a gallium complex from a targeting vector for targeted radiopharmaceuticals.
March 2023
Nicoline and Anna wrote a review in Annual Reviews of Physical Chemistry on Spectroscopic Studies of Clusters of Atmospheric Relevance! If you want to catch up on how folks are using spectroscopy and cluster chemistry to investigate structure, hydration, and other important aspects of clusters and particles in the atmosphere, this paper is a good starting point!
January 2023
Our first paper of 2023 appears in JACS: "The Competition between Hydrogen, Halogen, and Covalent Bonding in Atmospherically Relevant Ammonium Iodate Clusters." This work shows how a balance of intermolecular forces and bonding stabilizes clusters of ammonia and iodine oxides that may be important for particle formation in polar and costal regions. A lot of the work was done remotely by NSF REU student Danika Heaney (2021)!
December 2022
Congratulations to Emily Racow, who defended her thesis today!
November 2022
Another mass spec assist from our group on the Ngai groups recent success, "Excited-State Copper-Catalyzed [4 + 1] Annulation Reaction Enables Modular Synthesis of α,β-Unsaturated-γ-Lactams," (a mouthfull).
August 2022
Excited to announce that our NSF MRI proposal, "Development of a Mass Spectrometer for Isomer-selective Thermochemical, Structural, and Spectroscopic Characterization for Bimolecular Interactions," is being funded! In collaboration with Karena Chapman, Mike White, and Eszter Boros, we will construct a mass spec that merges our VTMS technique, vibrational spectroscopy, and electron total scattering measurements to directly measure interatomic distances in clusters, hydrated/solvated complexes, and host-guest systems with precisely known compositions and as a function of temperature.
May 2022
Congratulations to now-Dr. John Kreinbihl, our second Ph.D.! John will be starting a new career in data science at Travelers!
November 2021
Excited to have helped out, even a little on this collaboration with Ming-Yu Ngai's group at Stony Brook; Excited-State Copper Catalysis for the Synthesis of Heterocycles
July 2021
Our latest paper, a collaboration with the Christine Aikens' group, "Toward quantitative electronic structure in small gold nanoclusters," is out in the JCP special issue, "From Atom-Precise Nanoclusters to Superatom Materials." Here we present and example of the convergence of TD-DFT predictions and high resolution experimental electronic spectra of small, oblate gold nanoclusters. We also show that the widely-used superatomic model, which explains the qualitative features of nanocluster electronic structure, can be explicitly evaluated to provide semiquantitative energies.
June 2021
We are thrilled to receive funding from the DOE Early Career Research Program to establish the mechanisms by which atomically-precise nanoclusters catalyze CO2 reduction and optimize their efficacy! For more information, follow this link.
May 2021
John receives the Chemistry Award for Outstanding Doctoral Student. Great work John!
January 2021
A new paper is out: "Hydration motifs of ammonium bisulfate clusters show complex temperature dependence," in JCP. In this paper, we establish how water is accommodated in the different surface structural motifs of new particles and find that the apparent temperature dependence of the various competing sites is more complex than one might expect from typical thermodynamic considerations.
December 2020
Congratulations to Yi, the first Ph.D. graduate from the group! Best of luck with your new job!
November 2020
Thanks to Lai-Sheng Wang for the invitation to present a virtual seminar at Brown!
July 2020
Our paper, "Establishing the structural motifs present in small ammonium and aminium bisulfate clusters of relevance to atmospheric new particle formation," is now available in JCP. This paper discusses how structures of these small atmospheric clusters evolve with size and composition, with a particular focus on competition between isomers of similar stabilities.
June 2020
Chris presents a talk covering what we've learned about atmospheric new particle formation at the virtual Telluride Science Lecture Series. Thanks to Mark Kozak for organizing and Trevor Sears, Anne McCoy, Scott Reid, and Mike Heaven for the invitation!
May 2020
Yi receives the Maria Tzamarioudaki Memorial Award for Outstanding Doctoral Student, one of the two top awards for graduating Ph.D. students, and the Graduate Teaching Award, both from the Stony Brook Chemistry department. Way to go, Yi!
March 2020
We say goodbye to Dr. Anthony Cirri, who is starting a new career as an Associate Editor at AIP Publishing. We will all miss his. . . positivity.
The lab is shut down due to COVID-19! Only a scroll pump remains, vigilantly preventing water vapor from killing our detectors.
February 2020
Yi receives a 2019 PhD Award for Career Exploration from the Stony Brook Graduate and Postdoctoral Professional Development unit! This awards supports career exploration activities to help prepare promising students for careers outside of traditional academic research. Congratulations Yi!
Chris gives a hot topics talk on discussing our studies of gold nanoclusters at the GRC on Atomically-Precise Nanochemistry, and at the University of Wisconsin, Madison. Thanks Etienne Garand and Wisconsin PChem for a great visit!
Our JPCA Feature article has been featured on the cover of the February 27 issue of JPCA!
January 2020
Our JPCA Feature Article, "High Precision Electronic Spectroscopy of Ligand-Protected Gold Nanoclusters: Effects of Composition, Environment, and Ligand Chemistry," is now online! This is an overview of the work that led up to our studies, how our experiment works, why the spectra look the way they do, and an expanded discussion of our recent results on nanocluster surface chemistry.
Chris gives a talk on our recent progress in understanding New Particle Formation at the GRC on Molecular and Ionic Clusters.
December 2019
Our next gold nanocluster paper, "Hydride, Chloride, and Bromide Show Similar Electronic Effects in the Au9(PPh3)83+ Nanocluster," has just appeared at Chem Comm! The title is somewhat self-explanatory, but this paper is interesting because the hydride in this cluster has recently been proposed to behave like a metal, donating its electrons into the metal-localized orbitals. This suggests the possibility of "metallic halides," as one interpretation.
November 2019
Chris gives seminars at Washington University in St. Louis and University of Washington, the first ones talking about our recent nanocluster work. Thanks to Joe Fournier at WashU and Anne McCoy at UW for being gracious hosts!
September 2019
The first paper from our collaboration with the Boros group, "General Approach to Direct Measurement of the Hydration State of Coordination Complexes in the Gas Phase: Variable Temperature Mass Spectrometry," can be found at JACS! In this paper, we use variable-temperature ion traps to extract water binding thermodynamics for medically-relevant coordination complexes. Using this approach, we can estimate water binding in solution for metal ions that are not amenable to typical analytical techniques, and track trends in water binding across the periodic table!
We took delivery of a new laser system custom-built for us by Dean Guyer at Laservision! Continuous coverage of the electromagnetic spectrum from 194 nm to 16 microns! This will be used for isomer-specific studies and tag-free spectroscopy of gold nanoclusters, and was funded by the AFOSR through a DURIP.
Our paper, "Electrospray Ionization-Based Synthesis and Validation of Amine- Sulfuric Acid Clusters of Relevance to Atmospheric New Particle Formation," has appeared in Journal of the American Society of Mass Spectrometry! Using an atmospherically-isolated ESI source, we show that it is possible to generate a wide range of atmospherically-relevant clusters through vapor-condensation and exchange mechanisms with nascent ESI-generated clusters. This should broaden the scope of NPF studies based on mass spectrometry.
Finally, we welcome postdoc Jonathan Fagan to the group! Jonathan got his Ph.D. with Ben Lear at Penn State using magnetic spectroscopy to track ligand effects on gold nanoparticle electronic structure.
August 2019
Our first paper on gold nanoclusters, "Systematically tuning the electronic structure of gold nanoclusters through ligand derivatization," is available at Angewandte Chemie! We show that changing R groups of ligands precisely controls the HOMO-LUMO gap of prototypical gold nanoclusters, and thus can be used to quantitatively design functional nanoscale systems.
This paper has been highlighted at Nature Reviews Chemistry!
Furthermore, the Johnson group now has a twitter feed (for better or worse). . .
Chris and Anthony talk in the "Surface Chemistry and Structure in Ligand Protected Nanoparticles" symposium at the ACS National Meeting in San Diego (co-organized by Chris and Ben Lear).
June 2019
Chris gives one of two Flygare Award lectures at the 74th International Symposium on Molecular Spectroscopy in Champaign-Urbana, Illinois.
May 2019
Congratulations to Christina Kmiotek, M.S., who defended her thesis and walked in graduation!
April 2019
Chris and John both give talks at the Spring ACS meeting in Orlando. Chris presents the new particle hydration work in York at the proper Faraday Discussion. Our AFOSR DURIP proposal is funded, which allows us to dramatically improve our spectroscopic capabilities with a new laser for isomer-specific spectroscopy and a cryogenic ion trap for dispersed photoluminescence experiments to study energy transfer between nanoclusters and surface-bound
March 2019
Chris presents a plenary talk at Physics Days 2019 in Helsinki.
February 2019
Chris, Yi, and Anthony attend the Gordon Conference on Gaseous Ions, where Anthony wins a poster award! Chris gives seminars at Penn State (thanks Ben!) and UC San Diego (a homecoming).
January 2019
Our next paper, "Hydration Motifs of Ammonium Bisulfate Clusters of Relevance to Atmospheric New Particle Formation," has appeared at Faraday Discussions! In this paper, we identify the surface sites at which water preferentially binds to new atmospheric clusters, and examine their impact on the hydration of these clusters in the atmosphere.
Yi wins the Stony Brook Distinguished Travel Award, which will support her participation in the upcoming Gordon Conference on Gaseous Ions. Chris receives one of two Flygare Lecture Awards, featured talks at the 2019 International Symposium on Molecular Spectroscopy.
November 2018
Chris gives a seminar at Queens College in NYC. Thanks to Jianbo Liu - it was great to meet or reunite with folks!
October 2018
Chris gives seminars at University of Missouri and University of Georgia - both great visits! Special thanks to Arthur Suits and Mike Duncan!
September 2018
Our new paper, "Direct Link between Structure and Hydration in Ammonium and Aminium Bisulfate Clusters Implicated in Atmospheric New Particle Formation," has just appeared in The Journal of Physical Chemistry Letters! We show that hydration of new atmospheric particles can be explained by a simple accounting of the cluster structure, and that these clusters are likely to be at least somewhat hydrated in the atmosphere.
August 2018
A big month for the group. Hanna wins the Outstanding Student Poster Award at the 2018 ACS National meeting in Boston, and Anthony gives a talk in the Inorganic Spectroscopy session, both on the first results of our nano project. Chris goes on a tour of Europe, visits colleagues at the University of Helsinki, and gives talks there, at Kaiserslautern, and at the conference "Towards a Molecular Understanding of Atmospheric Aerosols" in Bad Honnef, Germany.
July 2018
Chris presents a poster on our recent work on new particle formation at the GRC on Molecular Interactions and Dynamics.
May 2018
We welcome Monica Passananti from the University of Helsinki who visits us for a week to look at hydration of new atmospheric particles!
April 2018
Hanna presents her first results on nanocluster synthesis and tandem mass spec in her poster, "Isolation and Characterization of Gold Nanoparticle Surface Stabilizing Species," at the Scientista Symposium in NYC.
March 2018
Emily gave a talk at the Spring ACS Meeting in New Orleans, entitled "Probing the internal temperature of cold trapped ion-molecule clusters." Kathy presented her poster, "Acid-catalyzed CH activation in atmospherically relevant clusters," as well!
February 2018
Our first paper, "The Interplay between Hydrogen Bonding and Coulombic Forces in Determining the Structure of Sulfuric Acid-Amine Clusters," has been accepted at The Journal of Physical Chemistry Letters! Check it out!
Chris gives a hot topics talk at the 2018 GRC on Molecular and Ionic Clusters, "Linking Structure and Growth in Atmospheric New Particle Formation."
January 2018
Welcome to new graduate student Hanna Morales Hernandez! Hanna will be working on the electronic structure of gold nanoclusters. A sad goodbye to Dr. Sarah Waller, who after an extremely productive postdoc starting up the lab, has moved on to make things that go into space at JPL. Good luck Sarah!
December 2017
This site has been updated with explanations of our research projects and experimental techniques. Check it out!
October 2017
We welcome Dr. Anthony Cirri to the group! Anthony is a postdoc who will be synthesizing and performing mass spec and spectroscopy to understand how ligands interact with metals in gold nanoclusters. It is a brave new world for him and us! We even have a small synthesis lab now. . .
August 2017
Eleanor presents the results of her research in a talk at the Fall ACS National Meeting. Best of luck to Eleanor, who has headed off to U.C. San Diego, and Jamie, who's headed back to Rhode Island. Thanks for all of your hard work! Hello to Thomas Schinkel, who joins us for the next two years working towards his Master's degree.
June 2017
We welcome Jamie Butalewicz to the lab for the summer as part of the Stony Brook REU program. Jamie will be helping us develop gas-phase ion chemistry and H/D exchange capabilities! We're also happy to receive funding from the ACS Petroleum Research Fund for work on the fundamentals of CH bond activation! Finally, Chris talks at the 7th International Workshop on Electrostatic Storage Devices in Lyon.
May 2017
Congratulations to Kathy Nickson, who was awarded an ACS Division of Physical Chemistry Undergraduate Award in Physical Chemistry! Kathy will spend the summer at Indiana University as an REU student, using photoelectron spectroscopy to understand the electronic structure of metal oxide clusters. Christina Kimotek graduated with her B.S. degree and will be starting her Master's degree this fall. Congratulations, Christina! Chris is grateful to the Air Force Research Laboratories Plasma Chemistry group, and especially Al Viggiano, for the opportunity to talk about new particle formation and to see the labs.
April 2017
Eleanor Castracane successfully defended her Master's Thesis on April 17, 2017. She will be starting her doctoral studies at the University of California, San Diego in September. Congratulations, Eleanor! Chris presents new results on new particle formation to Brookhaven National Lab's Aerosol Chemistry & Microphysics group.
February 2017
Sarah Waller serves as chair of the 2017 Gordon Research Symposium on Gaseous Ions, and gives a hot topics talk on our recent results in atmospheric new particle formation at the corresponding Gordon Research Conference. Nice work Sarah! Chris presents a poster outlining our upcoming metal nanoparticle spectroscopy experiments.
December 2016
Congratulations to Pengyan Liu, who graduated with her Bachelor's degree in Winter!
October 2016
Chris has been awarded a grant from the Young Investigator Program at the Air Force Office of Scientific Research. We will be using our composition-specific spectroscopy techniques to probe how metal nanoparticle surface chemistry affects electronic structure and charge and energy transfer. We're very thankful to the Air Force for supporting this project! Announcement SBU Press
September 2016
We welcome Stony Brook Undergraduates Kathy Nickson and Christina Kmiotek to the lab!
August 2016
Routine vibrational spectroscopy is now underway in the lab! Our first investigations of atmospheric new particle formation have begun! Thanks to Aakanksha, who in 7 weeks set us up with a computational framework for exploring the structures of these clusters.
June 2016
A busy month for the Johnson Lab. We are grateful to the National Science Foundation for funding our project on the molecular underpinnings of atmospheric new particle formation. Also, our instrument is working! Finally, we welcome Eleanor Castracane, who will be completing her M.S. with us, and Simons Summer Scholar Aakanksha Saxena, who comes to us from Scottsdale, AZ for seven weeks.
May 2016
Our tunable IR laser system is installed and producing prodigious power, and our cryogenic trap is at cryogenic temperatures. New data is imminent!
February 2016
Our permanent lab space has been renovated and we're moving in! Check the photos page for our progress.
January 2016
We're happy to have graduate students Yi Yang and John Kreinbihl joining the lab this semester!
November 2015
We've been hard at work and recorded our first reasonable orthogonal acceleration time-of-flight mass spectrum! Almost ready for lasers now. . .
July 2015
We're also happy to have Pengyan Liu joining the group for the summer and the upcoming school year. She will be graduating this year and is completing her senior research thesis with us!
June 2015
We welcome Anthony Chiarenza of Swarthmore College to the group for the summer through the NSF REU program at Stony Brook. Anthony will be helping us build and optimize our tandem time-of-flight mass spectrometer for our laser spectroscopy experiments. We're looking forward to a fun and productive summer!
May 2015
We got our ion source built and recorded our first quadrupole mass spectrum! Great work everybody! This source will be used to generate the molecular systems for our laser spectroscopy experiments.
April 2015
Chris and Sarah had a great time serving as judges for the WAC Lighting Foundation Invitational Science Fair in Port Washington, LI. All the projects were truly impressive and made us wonder what we were doing in high school. . .
February 2015
We're also excited about Emily Racow joining the group as our first graduate student! Welcome Emily!
January 2015
We're excited to have Sarah Waller join the group as a postdoctoral fellow from Indiana University. Sarah brings along considerable experience studying reactivity in heterogeneous systems and clusters. Welcome to the lab!
August 2014
The lab is established! Check the Photos page for updates on our progress. . .