title: Automatic generation of active coordinates for quantum dynamics calculations: application to the dynamics of benzene photochemistry.
abstract: A new practical method to generate a subspace of active coordinates for quantum dynamics calculations is presented. These reduced coordinates are obtained as the normal modes of an analytical quadratic representation of the energy difference between excited and ground states within the complete active space self-consistent field method. At the Franck-Condon point, the largest negative eigenvalues of this Hessian correspond to the photoactive modes: those that reduce the energy difference and lead to the conical intersection; eigenvalues close to 0 correspond to bath modes, while modes with large positive eigenvalues are photoinactive vibrations, which increase the energy difference. The efficacy of quantum dynamics run in the subspace of the photoactive modes is illustrated with the photochemistry of benzene, where theoretical simulations are designed to assist optimal control experiments.
authors: Department of Chemistry, Imperial College London, South Kensington, London SW7 2AZ, United Kingdom.
authors: Benjamin
authors: B
authors: Lasorne
authors: Fabrizio
authors: F
authors: Sicilia
authors: Michael J
authors: MJ
authors: Bearpark
authors: Michael A
authors: MA
authors: Robb
authors: Graham A
authors: GA
authors: Worth
authors: Lluìs
authors: L
authors: Blancafort
mesh_terms: D001554:Benzene / Q000737:chemistry*; D003198:Computer Simulation; D008956:Models, Chemical; D008958:Models, Molecular; D015394:Molecular Structure; D010777:Photochemistry; D011789:Quantum Theory
chemical_list: D001554:Benzene