Research Projects

Quantum Chemical Predictions for Clean Energy Materials

Together with the massive expertise in Density Functional Theory in the Martin Head-Gordon group, and the developmental team at Q-Chem, we employ Hybrid meta-GGA functionals to parse the molecular potential energy surface of clean energy materials.

Prediction of Multiple Hydrogen Ligation at the Primary Coordination Sphere of V(II) in a MOF.

Chakraborty, R., Carsch, K.M., Jaramillo, D.E., Yabuuchi, Y., Furukawa, H., Long, J.R. and Head-Gordon, M., 2022. The Journal of Physical Chemistry Letters, 13, pp.10471-10478.

With state-of-the art DFT simulations we predict the feasible ligation of two equivalents of hydrogen per open metal site, a discovery if realized experimentally can have a multiplicative effect for hydrogen storage in the solid state.

Ambient temperature hydrogen storage via vanadium(II)-dihydrogen complexation in a metal-organic framework

Jaramillo, D.E., Jiang, H.Z., Evans, H.A., Chakraborty, R., Furukawa, H., Brown, C.M., Head-Gordon, M. and Long, J.R., 2021. Journal of the American Chemical Society, 143(16), pp.6248-6256.

In this experimental collaboration with David Jaramillo (Long group), I simulated a Vanadium(II) MOF that displays near-optimal binding interactions for ambient temperature H2 storage. 

Observation of an Intermediate to H2 Binding in a Metal–Organic Framework

Barnett, B.R., Evans, H.A., Su, G.M., Jiang, H.Z., Chakraborty, R., Banyeretse, D., Hartman, T.J., Martinez, M.B., Trump, B.A., Tarver, J.D. and Dods, M.N., 2021. Journal of the American Chemical Society, 143(36), pp.14884-14894.

In this experimental collaboration with Brandon Barnett of the Long Research Group, we helped characterize a physisorbed intermediate to hydrogen binding with constrained optimizations along the molecular PES

Quantum Chemical Modeling of Pressure-Induced Spin Crossover in Octahedral Metal-Ligand Complexes

Stauch, T., Chakraborty, R. and Head‐Gordon, M., 2019. ChemPhysChem, 20(21), pp.2742-2747.

This collaboration with Prof. Tim Neudecker (née Stauch) models spin crossover in transition metal complexes using a Hydrostatic Compression Force Field inspired by DFT.  

Software for the frontiers of quantum chemistry: An overview of developments in the Q-Chem 5 package.

Epifanovsky, E., Gilbert, A.T., Feng, X., Lee, J., Mao, Y., Mardirossian, Chakraborty R, N., Pokhilko, P., White, A.F., Coons, M.P., Dempwolff, A.L. and Gan, Z., 2021. The Journal of chemical physics, 155(8), p.084801.

QChem 5 now has DFT-D4 dispersion corrections implemented!

Confinement Entropy from Numerical Partition Functions

Chakraborty R, Talbot J.J, Head-Gordon, Martin. In Prep

Simulations of confinement entropy are made challenging by exponential walls, both in electronic, and nuclear degrees of freedom. Here we simulate the effects of confinement on the entropy of gues molecules in nanoporous frameworks first under an uncoupled mode approximation, and with fully quantum mechanically coupled modes.

Reduced Density Matrices in Quantum Chemistry and Physics

Reduced density matrices enable compact descriptions of the many-body wavefunction and offer elegant solutions for the energy of a system, and allow for the detection of noise sans the exponential scaling that is entailed by a full-state tomography.

Sparsity of the wavefunction from the generalized Pauli exclusion principle

Chakraborty, R. and Mazziotti, D.A., 2018. The Journal of chemical physics, 148(5), p.054106.

We formulate here sparse representations for the N-fermion wavefunction based on General Pauli conditions that enforce global antisymmetry on N-fermion quantum states.

Here I derived sufficient conditions to detect noise in an N-fermion system sans a tomography of the N-particle density matrix.

Generalized Pauli conditions on the spectra of one-electron reduced density matrices of atoms and molecules

Chakraborty, R. and Mazziotti, D.A., 2014. Physical Review A, 89(4), p.042505.

This highlight from my graduate work studies the effect global antisymmetry constraints has on natural occupations number for pure quantum states that represent atoms and molecules.

Noise-Assisted Energy Transfer from the Dilation of the set of One-Electron Reduced Density Matrices

Chakraborty, R. and Mazziotti, D.A., 2017. The Journal of Chemical Physics, 146(18), p.184101.

This work looks at noise assisted energy transfer from a geometric perspective that involves the dilation of the set of accessible 1-RDMs with the introduction of quantum noise.

Role of Generalized Pauli Conditions in the Quantum Chemistry of Excited States

Chakraborty, R. and Mazziotti, D.A., 2016. International Journal of Quantum Chemistry, 116(10), pp.784-790.

Structure of the One-Electron Reduced Density Matrix from the Generalized Pauli Exclusion Principle

Chakraborty, R. and Mazziotti, D.A., 2015. International Journal of Quantum Chemistry, 115(19), pp.1305-1310.