Infrared spectra of hydrogen bonded species in solution

• Published in: Chemical physics Vol. 126; no. 2; pp. 263 - 290
• Main Authors: Boulil, Belkacem, Henri-Rousseau, Olivier, Blaise, Paul
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.1988; Elsevier
• Subjects: Atomic and molecular physics; Exact sciences and technology; Molecular properties and interactions with photons; Molecular spectra; Physics; Autocorrelation function; Chemical solution; Fourier transformation; Liouville equation; Theoretical study; Time dependent phenomenon; Vibrational transition; Sudden approximation; Apolar solvent; Effective Hamiltonian; Density operator; Infrared spectrum; Spectral density; Hydrogen bond
• ISSN: 0301-0104
• DOI: 10.1016/0301-0104(88)85038-9

The ν s(XH) hydrogen bond IR spectrum in liquid phase is studied by starting from the full quantum mechanical theory of Witkowski and Maréchal, and handling the dephasing process of the ν s(XH) mode by taking into account the random modulation resulting from the anharmonic coupling of the ν s(XH) with the ν s(XH…Y) mode. It is subject to intermolecular resonance energy exchange with the molecules of the inert solvent. The approach allows to obtain the spectral density of the ν s(XH) mode in terms of the following parameters: (i) the frequency of the fast mode in the absence of hydrogen bond, (ii) the frequency of the slow ν s(XH…Y) mode, (iii) a dimensionless parameter characterizing the anharmonic coupling between the fast ν s(XH) and the slow ν s(XH…Y) mode, and (iv) a damping parameter related to the strength of the resonant energy exchange between the ν s(XH…Y) mode and the molecules of the solvent. The model leads to results which are in agreement with experiment. It allows to connect the Witkowski and Maréchal approach in the gas phase with that of Bratos, and of Robertson and Yarwood in the liquid phase.