Journal of Physical Chemistry A, Vol.106, No.40, 9188-9195, 2002
A REMPI and ZEKE spectroscopic study of trans-acetanilide-H2O and comparison to ab initio CASSCF calculations
In this paper, two-color REMPI (resonance enhanced multiphoton ionization) and ZEKE (zero kinetic energy photoelectron) spectra of the trans-acetanilide-H2O complex are presented, extending our previous work on the trans-acetanilide monomer (Ullrich, S.; Muller-Dethlefs, K. J. Phys. Chem. A 2002, 106, 918 1). Spectral features are interpreted with the aid of ab initio CASSCF/cc-pVDZ calculations and compared to the monomer and related molecular systems, such as trans-formanilide-H2O (Ullrich, S.; et al. Phys. Chem. Chem. Phys. 2002, 4, 2897). In addition, the nature of the excess charge distribution in trans-acetanilide(+), and its modification upon solvation are discussed. Complexation of acetanilide with water leads to drastic changes in the So and S, state barrier heights for methyl group internal rotation and possibly reorientation of the methyl group compared to the monomer. Observations are interpreted by simulations of methyl rotor states in a V-3-V-6 potential.