Calculated frequencies and intensities associated with coupling of the proton motion with the hydrogen bond stretching vibration in a double minimum potential surface

Abstract

The influence of the coupling of the proton movement and the H bond stretching vibration in a double minimum potential energy surface on the energy levels, transitions, induced dipole moments and polarisabilities is calculated ub initio as a function of an electric field for the H,O: system. The high polarisability of the hydrogen bonds remains to a large extent unchanged due to the coupling. New types of transitions occur, particularly when the tunnelling frequency and the frequency of the bond stretching vibration are comparable in size. Especially in this case numerous Fermi resonances occur due to the shift of the energy levels in the electric field, which leads to a considerable increase in the number of transitions. It is shown that the change of the frequencies of the transitions due to the induced dipole interaction of the bonds with fields from their environment is a decisive cause of the variety of energy level differences observed as a continuous absorption in the i.r. spectrum of such systems.

Influence of stereochemistry, screening, and deuteration of long and short intramolecular easily polarizable hydrogen bonds on their infrared continua

“…Easily polarizable hydrogen bonds which are relatively long cause continua which are particularly intense in the region 2800-1800 cm-' and extend with less intensity toward smaller wave numbers, whereas easily polarizable hydrogen bonds which are relatively short absorb preferentially in the region 1600-600 cm-'. This relation between bond length and wave number distribution has already been studied with various systems (4, 11) and was confirmed theoretically (3,13). If these easily polarizable bonds are considered isolated, the proton polarizability is greatest with the long hydrogen bonds and decreases with the bond length (2-4a).…”

Proton vibrations in 2,4,6-trimethylpyridinium pentachlorophenolate

“…In 2,4,6-trimethylpyridinium pentachlorophenolate the stretching NH vibration is coupled with the ring and the methyl group vibrations. For very strong hydrogen bond this coupling is responsible for formation of the continuous absorption with Evans holes located at the frequencies of proton donor or proton acceptor vibrations [24][25][26][27][28]. The in-plane bending vibration band in the spectrum of 2,4,6-trimethylpyridinium pentachlorophenolate is shifted to 1686 cm À1 and the out-of-plane to 1191 cm À1 .…”

Infrared picosecond transient hole-burning studies of the effect of hydrogen bonds on the vibrational line shape

“…A great number of sophisticated theoretical models have been developed to describe vibrational line shapes, [2][3][4][5][6][7]22,23 some specifically addressing the effect of hydrogen bonds. [5][6][7]22,23 Here, we will give a brief review of the relevant theories, the concomitant predictions and previous applications of these theories to explain the experimental observations.…”

“…[5][6][7]22,23 Here, we will give a brief review of the relevant theories, the concomitant predictions and previous applications of these theories to explain the experimental observations.…”