Strong vibronic coupling effects in polarized IR spectra of the hydrogen bond in N-methylthioacetamide crystals

Effects of “excessive” exciton interactions in polarized IR spectra of the hydrogen bond in 2-butynoic acid crystals: Proton transfer induced by dynamical co-operative interactions involving hydrogen bonds

“…In these circumstances no coordination in the hydrogen isotope distribution between the hydrogen bridges of two neighboring chains in the unit cell appears [16][17][18]22]. In the other case, this phenomenon refers exclusively to the closely spaced hydrogen bonds, where each hydrogen bond in the mutually coupled system belongs to a different translationally nonequivalent chain penetrating a unit cell [23,24].…”

“…The first group comprises the systems where the H/D isotopic ''self-organization" concerns the neighboring hydrogen bonds within domains placed in fragments of each single hydrogen bond chain (pyrazole [17], imidazole [18], 4-thiopirydone [16] and formic acid [22]). The second group comprises crystals in which the H/D isotopic ''selforganization" mechanism involves the neighboring hydrogen bonds belonging to different, closely spaced chains (N-methylthioacetamide [23] and acetic acid [24]). …”

“…This remark concerns the intensity distribution, the temperature and the linear dichroic effects, measured in the crystal spectra, within the frequency range of the m X-H band contours [16][17][18][22][23][24]. This spectral behavior allows us to distinguish both ways of the occurrence of this process with the use of spectral studies performed on diverse hydrogen bonded crystalline systems.…”

“…by protons or deuterons. In the first case, the longitudinal domains are extended over several fragments of the hydrogen bond chains [16][17][18]22], whereas in the second case, the domains containing identical hydrogen isotope atoms, have the form of plain, disc-shaped structures, oriented perpendicularly to the chain direction in the crystal lattices [23,24].…”

“…These values govern the interactions between the pairs of translationally non-equivalent hydrogen bonds in the unit cells, for the crystal lattices with Z = 4, 8, etc. [16][17][18][22][23][24]. Complete information about the energies of exciton coupling can be obtained from the IR solid spectra, measured by using polarized light.…”