Rapid and accurate simulation of electron dynamics across nanostructures
Accurate first-principles modeling of electron dynamics is a challenging area of research. To follow the dynamics of molecular electron density one has to solve the time-dependent electronic Schrödinger equation (TDSE). Straight-forward extensions of common quantum chemistry methods to the time-dependent domain reveal density functional theory (DFT), or even the coupled cluster theories to be extremely unsuited for this purpose. In a series of studies, we have demonstrated linear equations of motions to be one of the fundamental requirements to reliably model electonic wavepacket dynamics, or coherent controlled state-to-state excitation. To this end, we have developed one of the most effcient implementations of the time-dependent configuration-interaction (TDCI) methodology to solve the TDSE. Our
implementation has been successfully applied to follow the electron transport across molecular wires and nanostructures terminating in a small metal cluster or a model gold surface. When combined with imaginary time propagation, or other variational schemes TDCI can be utilized also to perform time-independent task of computing the bound states. The present talk will provide an overview of the TDCI methodology and summarize the results of some recent applications.
 Raghunathan, et al., Critical examination of explicitly time-dependent density functional theory for coherent control of dipole switching Journal of Chemical Theory and Computation, 7 (2011) 2492.
 Ulusoy, et al., The multi-configuration electron-nuclear dynamics method applied to LiH, The Journal of chemical physics, 136 (2012) 054112.
 Ramakrishnan, et al., Control and analysis of single-determinant electron dynamics,
Physics Review A, 85 (2012) 054501.
 Ramakrishnan, et al., Electron dynamics across molecular wires: A time-dependent configuration interaction study, Chemical Physics, 420 (2013) 44.
 Ramakrishnan, et al., Charge transfer dynamics from adsorbates to surfaces with single active electron and configuration interaction based approaches, Chemical Physics, 446 (2015) 24.