Tags: Physical Seminar


Automated PES Exploration for Combustion Chemical Kinetics


Monte Carlo methods in ab initio quantum chemistry: FCIQMC and its precursors

Abstract: Monte Carlo methods have been used in quantum chemistry for decades to obtain high-accuracy solutions to the electronic Schrodinger equation. These stochastic methods are useful due to their arbitrary accuracy and ease of implementation compared to deterministic methods. The recently-developed full configuration interaction quantum Monte Carlo (FCIQMC) method [Nature, 2013, 493 (7432), 365–370] is perhaps the most promising of these…


Using Lasers to Poke at Timescales in Simple and Complex Systems

Since their development in the 1960s, lasers have been used in a myriad of ways to study and influence chemical reactions. In this talk, three topics will be addressed: photodissociation, metallized polymers, and large-cluster reactivity. The role of the laser in probing and altering reaction timescales will be examined.


Characterization of Dynamical Resonances using cryo-SEVI Transition State Spectroscopy

  Dynamical resonances are quasi-bound quantum states that exist in the vicinity of a transition state for a bimolecular reaction.  These resonances are predicted to be ubiquitous among chemical reactions and can mediate reactivity at low temperatures. However, only a handful of resonances have been definitively observed or characterized.  Slow photoelectron velocity-map imaging of cryogenically cooled anions (cryo-SEVI) is a…


Bootstrap Embedding: A Fragmentation Approach for Molecules

  Abstract: Fragment embedding divides the description of a system into smaller and more cost-friendly pieces for computation. For systems with strong correlation, the challenge is to properly describe the entanglement effect of the environment on the embedded fragment. The recently developed Bootstrap Embedding [JCTC, 15, 4497 (2019)] uses overlapping fragments to improve fragment description at the edges,  and will be reviewed in…


Automatic Differentiation and Computational Chemistry

Automatic Differentiation (AD) is a general method for obtaining derivatives of arbitrarily complex functions in computer programs. Naturally, such a tool would seem invaluable to computational chemistry applications. Some current developments and limitations of applying AD to quantum chemistry techniques presented in the literature are discussed.   


Janus: An Extensible Open-Source Software Package for Adaptive QM/MM Methods


Photoisomerization Dynamics of Stilbenes: Evidence for the Perpendicular Phantom State


PES-Learn: An Open-Source Software Package for the Automated Generation of Machine Learning Models of Molecular Potential Energy Surfaces


Sulfurous Acid: Predicting a Spectrum and Setting the Surface Straight

Sulfurous acid is hypothesized to be a nucleation center for aerosols, but its isolation and characterization have been described as one of the greatest challenges of inorganic chemistry. Consequently, most information about sulfurous acid has come from the more than twenty theoretical studies examining it. However, none of them have performed a comprehensive examination of this surface, and the studies are plagued by problems ranging from basis…
Subscribe to Physical Seminar