Raman spectroscopic studies on matrix-isolated arsenic and antimony molecules As 4 and Sb 4 in noble gas matrices

Abstract

The Raman spectra of As 4 and Sb 4 molecules have been studied in neon, argon, krypton, and xenon matrices at 7 K. The vibrational frequencies of the As 4 molecule are up to 17 cm −1 higher than the experimental gas phase data. This evident blue-shift is not caused by matrix effects but originates from an underestimation of the fundamentals in the gas phase as a course of the elevated temperatures. The observed frequencies of As 4 and Sb 4 show a linear dependence toward the matrix host polarizability. Extrapolated values for zero polarizability which best represent a free molecule, are considered fundamental frequencies. The general valence force fields of As 4 and Sb 4 were calculated from the extrapolated frequencies.