S_2分子~3Δ_g(3dπ_g)里德堡态双光子共振电离的研究

Two-Photon Resonance Ionization Study of the ~3Δ_g（3dπ_g） Rydberg State of S_2

在306-321 nm单光子波长范围内采用REMPI光谱方法研究S2分子3Δg里德堡态光谱,第一次报道了混合同位素分子32S34S的REMPI光谱,得到3Δg态精确的分子常数,对分子32S32S,ωe=800.1(25)cm-1,ωeχe=3.4(7)cm-1,Be=0.31564cm-1,αe=0.00165cm-1,对同位素分子32S34S,ωe=788.0(8)cm-1,ωeχe=3.3(2)cm-1,Be=0.30613cm-1,αe=0.00160cm-1.根据32S32S和32S34S的谱带基线确定同位素位移(Δν=0ν(32S32S)-ν0(32S34S)),0-0谱带同位素位移为0.2(5)cm-1,1-0谱带为11.8(3)cm-1,2-0谱带为23.3(5)cm-1,对于0-1谱带,为-10.2cm-1.讨论了3Δg态不对称自旋-轨道分裂,不对称分裂是源于1Δ2g态扰动.

The 3Δg Rydberg state of S2 is reexamined by resonance-enhanced multiphoton ionization（REMPI） spectroscopy in the single-photon wavelength region of 306-321 nm and the REMPI spectrum of the mixed 32S34S isotopomer is reported for the first time.Precise molecular constants of the 3Δg state were obtained,ωe=800.1（25）cm-1,ωeχe=3.4（7）cm-1,Be=0.31564cm-1,and αe=0.00165cm-1 for 32S32S and ωe=788.0（8）cm-1,ωeχe=3.3（2）cm-1,Be=0.30613cm-1,αe=0.00160cm-1 for 32S34S.The isotope shifts（Δν=ν0（32S32S）-ν0（32S34S）） were determined from the band origins of 32S32S and 32S34S,0.2（5）cm-1 for the 0-0 band,11.8（3）cm-1 for the 1-0 band,23.3（5）cm1 for the 2-0 band,and-10.2（4）cm-1 for the 0-1 band.The asymmetric spin-orbit splitting is discussed and attributed to the perturbation of the 1Δ2g state.