Triplet-singlet emission spectra of p-benzoquinone-H4 and -D4 in the vapour state

Abstract

The visible emission spectra of p-benzoquinone-H4 and -D4 have been recorded, in the vapour state, in the presence of flowing vapour of toluene. The spectra lie in the region 6843 Å to 5226 Å. The band at 18683 cm-1 has been identified as the OO band for both the p-benzoquinones. The frequencies of p-benzoquinone-D4 show small violet shift relative to the frequencies of p-benzoquinones-H4. The spectra have been analysed with the help of three totally symmetric ground state vibrations: p-benzoquinone-H4/D4: 1675/1667 (CO stretching); 761/735 (ring breathing) and 437/423 (ring deformation, in the molecular plane) cm-1. The emission involves 3Au → 1Ag transition in both cases. © 1965.