In Dmitry’s first paper in the group, he demonstrates that numerically exact solution of the vibrational Schrodinger equation in the adiabatic representation around a conical intersection in a finite basis is only possible if that basis contains discontinuous functions.  We demonstrate an approach based on a basis of discontinuous functions on a 2-D model and discussed how our approach could be extended to more dimensions.

Check out our recent collaborative effort with the Dantus group  and Ned Jackson at MSU and researchers at Kansas State University in Nature Communications.  In conjunction with experiment, Dantus group member Muath Nairat conducted GPU-accelerated AIMD simulations of an intriguing chemical reaction: the formation of H₃⁺ upon double ionization of small organic molecules in strong laser fields.  It is found that H₃⁺ forms when a roaming H₂ molecule abstracts a proton from the remaining molecular fragment. Our GPU-accelerated CASCI code enabled excellent sampling of trajectories on a potential energy surface that provided a balanced treatment of closed shell and radical reaction pathways.

Check out Wei-Tao’s new paper in Sci. Rep. in which we discuss the effect of Stokes shift on the efficiencies of translucent luminescence solar concentrators based on cyanine dyes.

Sadly, this work is dedicated to the memory of great friend and scientist Seth Olsen who passed away suddenly earlier this year.  Cyanine dyes were among our common interests, and I learned a lot about them from reading his papers and talking to him.  He is greatly missed.

Better late than never:  Check out Scott’s paper in JCTC on rank-reduced full CI.  RR-FCI is an approximation to full CI that is scalable up to 30 electrons in 30 orbitals by representing the CI vector as a matrix of reduced rank.  This work was a collaboration with the Martinez and Koch groups.

Check out Wei-Tao and Scott’s paper on our novel GPU-accelerated algorithm for time-dependent complete active space configuration interaction, published in JCTC.  It’s fast, and speed aside, time-dependent configuration interaction has many advantages over RT-TDDFT.  Nice work guys!

Check out Wei-Tao’s new paper in Chem. Sci.  It describes an ab initio molecular dynamics (AIMD) study of non-radiative recombination in silicon nanoparticles (up to 1.7 nm) with dangling bond defects on their surfaces.  These mark the first AIMD studies of semiconductor nanomaterials carried out using a multireference description of the electronic structure capable of accurately modeling the PES in the neighborhood of conical intersections involving the electronic ground state.

Also, congrats to Wei-Tao on his first first-author paper in the Levine group!

Check out our recent paper with Ed Hohenstein reporting analytic gradients for the CISNO-CASCI method.  CISNO is an efficient, well-behaved, and size-intensive alternative to SA-CASSCF for modeling nonadiabatic dynamics near conical intersections.

Check out our most recent collaborative effort with the Dantus group, published in Scientific Reports.  This paper describes a combined experimental and theoretical study of the mechanisms of H₃⁺ formation from methanol in a strong laser field.  Two different mechanisms were observed in AIMD simulations at the full-valence CAS level (carried out by Muath using Scott’s GPU-accelerated CAS code).

Also check out this awesome video on this work, created by Dantus-group undergraduate Patrick Pawlaczyk.