JOURNAL OF CHEMICAL PHYSICS, v.158, no.21, pp.214303
Abstract
The coupling between the symmetric (v(s)) and antisymmetric (v(a)) OD stretch modes of monomeric D2O in CHCl3 is investigated using polarization-dependent two-dimensional infrared (2D IR) spectroscopy supported by numerical 2D IR simulations based on the exciton-band theory. The relationship between the local modes' and the exciton states' parameters is systematically studied, including center frequencies, diagonal anharmonicities, coupling, and off-diagonal anharmonicity. The mean coupling between v(s) and v(a) is accurately evaluated to be -49.96 +/- 0.14 cm(-1). The degree of relaxation in the harmonic approximation is quantified, and the angle between the exciton-state dipoles is accurately evaluated to be 101.4 degrees +/- 3.6 degrees. In addition, the effect of the local-mode frequency correlation on the resulting exciton-state frequency correlation and the spectral shape of the linear and 2D IR spectra are also investigated.