Academic Appointments


All Publications


  • InteraChem: Exploring Excited States in Virtual Reality with Ab Initio Interactive Molecular Dynamics. Journal of chemical theory and computation Wang, Y., Seritan, S., Lahana, D., Ford, J. E., Valentini, A., Hohenstein, E. G., Martinez, T. J. 2022

    Abstract

    InteraChem is an ab initio interactive molecular dynamics (AI-IMD) visualizer that leverages recent advances in virtual reality hardware and software, as well as the graphical processing unit (GPU)-accelerated TeraChem electronic structure package, in order to render quantum chemistry in real time. We introduce the exploration of electronically excited states via AI-IMD using the floating occupation molecular orbital-complete active space configuration interaction method. The optimization tools in InteraChem enable identification of excited state minima as well as minimum energy conical intersections for further characterization of excited state chemistry in small- to medium-sized systems. We demonstrate that finite-temperature Hartree-Fock theory is an efficient method to perform ground state AI-IMD. InteraChem allows users to track electronic properties such as molecular orbitals and bond order in real time, resulting in an interactive visualization tool that aids in the interpretation of excited state chemistry data and makes quantum chemistry more accessible for both research and educational purposes.

    View details for DOI 10.1021/acs.jctc.2c00005

    View details for PubMedID 35649124

  • InteraChem: Virtual Reality Visualizer for Reactive Interactive Molecular Dynamics JOURNAL OF CHEMICAL EDUCATION Seritan, S., Wang, Y., Ford, J. E., Valentini, A., Gold, T., Martinez, T. J. 2021; 98 (11): 3486-3492
  • Selective bond formation triggered by short optical pulses: quantum dynamics of a four-center ring closure PHYSICAL CHEMISTRY CHEMICAL PHYSICS Valentini, A., van den Wildenberg, S., Remacle, F. 2020; 22 (39): 22302–13

    Abstract

    We report bond formation induced by an ultrashort UV pulse. The photochemical process is described by quantum dynamics as coherent electronic and nuclear motions during the ultrashort pulse induced ring closure of norbornadiene to quadricyclane. Norbornadiene consists of two ethylene moieties connected by a rigid (CH2)3 bridge. Upon photoexcitation, two new sigma bonds are formed, resulting in the closure of a four-atom ring. As a medium-sized polyatomic molecule, norbornadiene exhibits a high density of strongly coupled electronic states from about 6 eV above the ground state. We report on inducing the formation of the new bonds using a short femtosecond UV pulse to pump a non-equilibrium electronic density in the open form that evolves towards the closed ring form. As the coherent electronic-nuclear coupled dynamics unfold, the excited states change character through non-adiabatic interactions and become valence states for the two new C-C bonds of quadricyclane. Our three-dimensional fully quantum dynamical grid simulations during the first 200 fs show that short UV pulses of different polarization initiate markedly different initial non-equilibrium electronic densities that follow different dynamical paths to the S0/S1 conical intersection. They lead to different initial relative yields of quadricyclane, thereby opening the way to controlling bond-making with attopulses.

    View details for DOI 10.1039/d0cp03435e

    View details for Web of Science ID 000581179800012

    View details for PubMedID 33006338