Matrix effect on the IR spectra of sodium and potassium acid bifluorides in alkali halide pressed disks

IR spectra of sodium and potassium acid bifluorides were recorded in different alkali halide matrices, and the values of the vibrational modes V _2'', V₃ and (v₁ + V₃) were obtained. The value of v₁ was calculated by subtraction of v₃ from (v₁+v₃. The observed frequencies for these vibrational modes are dependent on the alkali halide matrix used. These frequencies are correlated with the sum of the ionic radii of the matrix anion and cation, (R_anion + R_cation), which is in correspondence with the formation of a solid solution between the sample and the matrix. These correlations are interpreted on the basis of the proton motion in the box formed by the bifluoride anion inserted in an anion site of the matrix.