Analytic potential energy surfaces (PESs) and state couplings of the ground and two lowest singlet excited states of thioanisole (C6H5SCH3) are constructed in a diabatic representation based on electronic structure calculations including dynamic correlation. They cover all 42 internal degrees of freedom and a wide range of geometries including the Franck-Condon region and the reaction valley along the breaking S-CH3 bond with the full ranges of the torsion angles. The parameters in the PESs and couplings are fitted to the results of smooth diabatic electronic structure calculations including dynamic electron correlation by the extended multi-configurational quasi-degenerate perturbation theory method for the adiabatic state energies followed by diabatization by the fourfold way. The fit is accomplished by the anchor points reactive potential method with two reactive coordinates and 40 nonreactive degrees of freedom, where the anchor-point force fields are obtained with a locally modified version of the QuickFF package. The PESs and couplings are suitable for study of the topography of the trilayer potential energy landscape and for electronically nonadiabatic molecular dynamics simulations of the photodissociation of the S-CH3 bond.
|Original language||English (US)|
|Journal||Journal of Chemical Physics|
|State||Published - Feb 14 2017|
Bibliographical noteFunding Information:
The authors are grateful to Xuefei Xu, Ke R. Yang, Jingjing Zheng, Chad Hoyer, Junwei Lucas Bao, and Rubén Meana Pañeda for many helpful discussions. This work was supported in part by the U.S. Department of Energy, Office of Basic Energy Sciences, under Grant No. DE-SC0008666. S.L.L. was also supported by the Frieda Martha Kunze Fellowship and a Doctoral Dissertation Fellowship at the University of Minnesota. Computational resources were provided by the University of Minnesota Supercomputing Institute and by the DOE Office of Science User Facilities at Molecular Science Computing Facility in the William R. Wiley Environmental Molecular Sciences Laboratory of Pacific Northwest National Laboratory and at the National Energy Research Scientific Computing Center (Contract No. DE-AC02-05CH11231).
© 2017 Author(s).