Raman Spectra of Molecular Crystals with Strong Hydrogen Bonds N-H⋯N in the Temperature Range of 5–300 K

In this work, Raman spectra are recorded for the crystals of compounds containing N-H⋯N hydrogen bonds demonstrating proton tautomerism. The spectra are obtained in the temperature range of 5–300 K. The starting temperature of proton tunneling on the bonds is determined from the temperature dependence of peak positions of translational vibrations N⋯N participating in hydrogen bonding. The beginning of proton ordering is found from the half-width temperature dependence. Both parameters of proton tautomerism correlate with the type and strength of the hydrogen bond.