Fourier-Raman spectra of alkali metal and thallium hydrogen phthalate single crystals

Polarized Fourier-Raman spectra of K, Rb and Tl hydrogen phthalates are studied at the 1064 nm excitation. The frequencies of internal vibrations in hydrogen phthalates are assigned to vibrations of orthophenylene and carboxyl groups. A substitution of K for Rb and Tl gave rise to a small low-frequency shift of vibrations. It is observed the multiband structure of the stretching OH-vibrations due to the fermi-resonance interactions. A number of additional bands are found in the spectra of deuterium potassium acid phthalate. It is suggested that only the partial substitution of hydrogen atoms for deuterium takes place in both orthophenylene and carboxyl groups.