Abu’s paper has been published in Molecular Physics! In this study, we take the formulation of vibrational heat-bath configuration interaction by the Berkelbach group and implement an alternative formulation by explicitly calculating and storing all Hamiltonian matrix elements. Like a lot of quantum chemistry methods, which one of the formulations is best seems to depend on the system and the level of accuracy required. Our technique appears to work better for ethylene oxide, while the previous formulation does better for naphthalene. Link is here.
New Year, New JCTC Paper
Jonathan’s paper has been published in JCTC. In this paper, we implement a new multicomponent CASSCF method using the multicomponent heat-bath CI algorithm as the CI solver. We previously used this CI solver in our multicomponent CISDTQ study. This allows us to use extremely large active spaces relative to previous multicomponent CASSCF studies. It turns out dynamical correlation is important for obtaining accurate protonic densities (which really isn’t that great of a surprise), as we find that very large active spaces are required for even qualitatively accurate protonic densities. We hope to have plenty more to come on this and similar topics in the future. Link is here: https://pubs.acs.org/doi/full/10.1021/acs.jctc.0c01191
New Graduate Student!
A new graduate student, Ethan Lesko, has joined the group! Ethan previously worked with us in the summer of 2019 on the VASCI study before he entered graduate school and we are happy to have him back. Welcome Ethan!
Machine Learning-Based Nonadiabatic Dynamics Paper in JPCA!
M’s paper has been published in JPCA. This paper has been a long time coming and was one of the first things we started working on after joining Mizzou, so we are quite pleased to see its completion. In the paper, we introduce a simple modification of Wigner sampling for generating training data for machine learning-based nonadiabatic dynamics. As is hinted at in the conclusions, M is rapidly working on extending the method to electronic Hamiltonians and we hope to continue to expand and follow up on this study in the future. Link is here: https://doi.org/10.1021/acs.jpca.0c07376
Multicomponent OOMP2 Paper in JCP
Jonathan’s paper has been published in JCP! In it we show that in multicomponent OOMP2 the electron-electron correlation can be included after the orbital-optimization procedure with essentially no loss in accuracy for protonic properties relative to the original multicomponent OOMP2 method. Using the results in this paper, we hypothesize that in all multicomponent orbital-optimized methods, it is sufficient to perform the orbital-optimization procedure solely in the presence of electron-proton correlation. Link is here: https://doi.org/10.1063/5.0006743