The optical absorption and magnetic circular dichroism of MnO 3Cl in the vapor phase

Abstract

Optical absorption and magnetic circular dichroism (MCD) spectra of gaseous MnO 3Cl in the region 4000–8000 Å have been measured. The optical absorption spectrum showed an intense band in the visible and a weak band in the near infrared. The visible transition has two 0-0 bands which could be assigned as 1A 1 → 1A 1, 1E( 1T 2). The trigonal splitting of this 1T 2 state is E( 1A 1)- E( 1E) ≈ 80 cm −1. The MCD shows an anomalous Franck-Condon pattern and evidence was found for a vibronic interaction of the excited 1E state with an e-type vibrational mode. The far red transition can most likely be assigned to the 1A 1 → 1E( 1T 1) transition. The rovibrational transitions have bandheads in the R-branch. The MCD resolves the rotational structure of the vibronic bands to a great extent.