Brorsen Lab

The group has seen some turnover in the last month.

First, Jonathan has taken Horace Greeley’s advice and headed west to Stanford for graduate school. We wish him the best and are excited for his future.

We also have two new members of the group!

The first is Naresh Alaal, who is a postdoctoral researcher coming to us from Kaust in Saudi Arabia. Naresh was supposed to start in April of 2020, but then the pandemic happened, so we were unable to get him a visa. We are thrilled that he is finally able to start working with us.

The second is Gabbie Tucker, who is a Stevens Scholar for the summer and is currently an undergraduate at the College of the Ozarks. Already in her short time here, she has shown a lot of potential as a future theoretical chemist and we are enjoying seeing her grow as a researcher.

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.

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

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!

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