Bandshapes of Nonisolated H-Bonds

Infrared Spectroscopy of H-Bonded Systems Theoretical Descriptions 

The 7-phonon band corresponds toa Eq E transition for various values of N. The -1-phonon band is a hot band , that is, as defined above, a band that starts from states Fif with N greater than 0 (the corresponding E final state should have A 1 0). The 0-phonon band is sharp. The 1-phonon band is broader, because the energies of the phonons are spread over a band of finite width. It makes the 2-phonon band broader, and the following 3-phonon bands even more so. The centres and total widths of these bands are still given by eqs. (5.A43) of the appendix of this chapter, or eq. (5.A51) if several interacting H-bonds are present in the crystal. 

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