Vibrational and orientation relaxation of tetrafluoroborate ion in the medium of a dipolar aprotic solvent

Using the methods of Raman and IR absorption spectroscopy by the shape of vibration band ν1(A1) of tetrafluoroborate ion, vibrational and orientational relaxation of non-associated anion in solutions of potassium and lithium tetrafluoroborates in dimethyl sulfoxide (DMSO) in the temperature range of 293-373 K is studied. It is ascertained that collision dephasing of intraionic vibrations is the main mechanism of vibrational relaxation. Oriented motion of tetrafluoroborate ion in dipolar aprotic solvent has the character of narrow angle rotational diffusion with average angular pitches of rotation of about 2-3 deg