Molecular electronic Raman transitions and magnetic susceptibility of the chromocene molecule

Abstract

Raman spectra of solid chromocene have been recorded in the region 10–1200 cm−1 at ambient and low temperatures. Assuming a D5d geometry the bands at 283 cm−1 ν4(a1g), 370 cm−1 ν16(e1g), and 1094 cm−1 ν3(a1g) are assigned to be of vibrational origin, while two electronic Raman bands have been observed with shifts of 35 and 55 cm−1. The series of transitions with the 0′–0 at 35 cm−1 indicate a shift between the ground state and an excited state coupled to the torsional mode ν6(a2g) with frequency 21 cm−1. This mode becomes totally symmetric and hence Raman active if the symmetry is lowered to C5. The electronic Raman data are used to choose a set of parameters and compute the magnetic moment for small distortions from D5d. The magnetic moment <μ (T) ≳ so computed is compared with available experimental data.