Structural-thermodynamic analysis of the relationship between the half-width and the position of the absorption band maxima in the low-frequency IR spectra of liquid systems

Демидов В.Н., Пузенко В.Г., Савинова А.И. Структурно-термодинамический анализ взаимосвязи между полушириной и положением максимума полос поглощения в низкочастотных ИК спектрах жидких систем // Оптический журнал. 2007. Т. 74. № 4. С. 9–15.

Demidov V.N., Puzenko V.G., Savinova A.I. Structural-thermodynamic analysis of the relationship between the half-width and the position of the absorption band maxima in the low-frequency IR spectra of liquid systems [in Russian] // Opticheskii Zhurnal. 2007. V. 74. № 4. P. 9–15.

V. N. Demidov, V. G. Puzenko, and A. I. Savinova, "Structural-thermodynamic analysis of the relationship between the half-width and the position of the absorption band maxima in the low-frequency IR spectra of liquid systems," Journal of Optical Technology. 74 (4), 230-235 (2007). https://doi.org/10.1364/JOT.74.000230

The cluster-continuum approximation of the method of thermodynamic functionals of the internal structural coordinates is used to carry out a theoretical structural-thermodynamic analysis of the relationship between the half-width and the position of the absorption-band maxima in the low-frequency IR spectra of liquid systems. By considering the thermodynamic theory of fluctuations, it is shown that this relationship is strictly functional and is determined by the ratio of the effective cluster heat capacities or of the generalized thermodynamic susceptibilities in the ground and excited states. For molecular liquids, it follows from this theory that the half-width is directly proportional to the position of the low-frequency IR absorption-band maxima, with a slope close to unity.