Laser-induced fluorescence spectra and torsional potential energy functions of jet-cooled 4,4 '-dimethyl-trans-stilbene Academic Article uri icon

abstract

  • The laser-induced fluorescence excitation spectra of jet-cooled 4,4-dimethyl-trans-stilbene have been recorded, and the phenyl and methyl internal rotation levels have been assigned for the S0 and the S1(,*) electronic states. Dispersed fluorescence spectra and vapor-phase Raman spectra were utilized to help assign the low-frequency vibrations in the electronic ground state. The methyl torsions have energy levels and potential functions very similar to those of m-xylene. The S0 state has V6 = 15 15 cm-1 (negligible barrier), while S1 has V3 = 85 10 cm-1 and V6 = -30 20 cm-1. The barrier to simultaneous internal rotation of the phenyl groups in S0 was found to be 3100 cm-1. This is identical to that of trans-stilbene within experimental error. For the S-1 state, the barrier is 3140 cm-1 as compared to 3000 cm-1 for trans-stilbene. The barrier to rotation about the C=C bond in the S0 state was estimated to be 41 5 kcal/mol based on one assigned frequency. In the S1 state the trans-twist barrier was estimated to be approximately 2400 cm-1.

published proceedings

  • JOURNAL OF PHYSICAL CHEMISTRY A

author list (cited authors)

  • Arp, Z., Chiang, W. Y., Laane, J., Sakamoto, A., & Tasumi, M.

citation count

  • 8

complete list of authors

  • Arp, Z||Chiang, WY||Laane, J||Sakamoto, A||Tasumi, M

publication date

  • April 2002