HKrF in solid krypton

A new krypton-containing compound, HKrF, has been prepared in a low-temperature Kr matrix via VUV photolysis of the HF precursor and posterior thermal mobilization of H and F atoms. All three fundamental vibrations have been observed in the FTIR spectra at similar to1950 cm(-1) (H-Kr stretch), similar to650 cm(-1) (bending), and similar to415 cm(-1) (Kr-F stretch). Two distinct sites of HKrF have been identified. The energy difference between the H-Kr stretching vibrations for the two sites is remarkably large (26 cm(-1)), indicating a strong influence of the environment. In annealing after the photolysis of the precursor, HKrF is formed in two different stages: at 13-16 K from closely trapped H+F pairs and at T>24 K due to more extensive mobility of H and F atoms in the matrix. HKrF in a less stable site decreases at temperatures above 32 K, the other site being stable up to the sublimation temperature of the matrix. The photodecomposition cross section for HKrF has been measured between 193 and 350 nm and compared with the cross sections of the previously reported HArF and HKrCl molecules. The condensed-phase VSCF (vibrational self-consistent field) calculations suggest that the more stable form is a single-substitutional site and the less stable form is a double-substitutional site of HKrF in solid Kr. The gas to matrix shifts for these sites are predicted to be +(9-26) cm(-1) for the H-Kr stretching and the bending vibrations and -(7-10) cm(-1) for the Kr-F stretching vibrations. (C) 2002 American Institute of Physics.