Molecular dynamics in low-spin excited states

Nonadiabatic Car-Parrinello Molecular Dynamics

Physical Review Letters, 88(16):166402.
Nikos L Doltsinis and Dominik Marx (2002)

Abstract

An extension of Car-Parrinello (CP) molecular dynamics for efficient treatment of electronically nonadiabatic processes is presented. The current approach couples the S1 restricted open-shell Kohn-Sham excited state to the S0 ground state using a surface hopping scheme. Efficient evaluation of the nonadiabatic couplings is achieved by exploiting the available wave function time derivatives. Since the computational cost scales linearly with the number of excited states, the technique makes possible nonadiabatic ab initio simulations of systems of similar complexity to those typically studied by standard CP methods. It is thus ideally suited to study the photochemistry of large molecules, particularly in condensed phases.

URL: http://dx.doi.org/10.1103/PhysRevLett.88.166402

First principle molecular dynamics involving excited states and nonadiabatic transitions

Journal of Theoretical and Computational Chemistry (JTCC), 1(2):319-349.
N L Doltsinis and D Marz (2002)

Abstract

Extensions of traditional molecular dynamics to excited electronic states and non-Born–Oppenheimer dynamics are reviewed focusing on applicability to chemical reactions of large molecules, possibly in condensed phases. The latter imposes restrictions on both the level of accuracy of the underlying electronic structure theory and the treatment of nonadiabaticity. This review, therefore, exclusively deals with ab initio “on the fly” molecular dynamics methods. For the same reason, mainly mixed quantum-classical approaches to nonadiabatic dynamics are considered.

URL: http://dx.doi.org/10.1142/S0219633602000257

Molecular dynamics in low-spin excited states

The Journal of Chemical Physics, 108(10):4060–4069.
Irmgard Frank, Jurg Hutter, Dominik Marx, and Michele Parrinello (1998)

Abstract

A Kohn–Sham-like formalism is introduced for the treatment of excited singlet states. Motivated by ideas of Ziegler’s sum method and of restricted open-shell Hartree–Fock theory, a self-consistent scheme is developed that allows the efficient and accurate calculation of excited state geometries. Vertical as well as adiabatic excitation energies for the n→π* transitions of several small molecules are obtained with reasonable accuracy. As is demonstrated for the cis-trans isomerization of formaldimine, our scheme is suited to perform molecular dynamics in the excited singlet state. This represents a first step towards the simulation of photochemical reactions of large systems.

URL: http://dx.doi.org/10.1063/1.475804