报告题目：Identification of four rotamers of 3-methoxystyrene by REMPI and MATI spectroscopy

报 告 人：曾文碧,中央研究院原子分子科學研究所（台湾）

报告时间：6月24日 上午10：30

报告地点：理科楼三楼报告厅

报告摘要：We report the vibronic and cation spectra of four rotamers of m-methoxystyrene, recorded by using the two-color resonant two-photon ionization and mass-analyzed threshold ionization techniques. The excitation energies of the S1 ← S0 electronic transition are found to be 32 767, 32 907, 33 222, and 33 281 cm？1; and the corresponding adiabatic ionization energies are 65 391, 64 977, 65 114, and 64 525 cm？1 for these isomeric species. Most of the observed active vibrations in the electronically excited S1 and cationic ground D0 states involve in-plane ring deformation and substituent-sensitive bending motions. It is found that the relative orientation of the methoxyl with respect to the vinyl group does not influence the vibrational frequencies of the ring-substituent bending modes. The two dimensional potential energy surface calculations support our experimental finding that the isomerization is restricted in the S1 and D0 states.