VA族元素氢化物的紫外光解和多光子电离Ⅱ. PH3的多光子电离光谱

用染料激光器在波长为300-640 nm范围内扫描, 观察到PH_3的一系列多光子电离光谱。其中351-398 nm的近二十条谱带, 其能级间隔约263 cm~(-1), 拟归属于通过Ã态的(2+1)电离谱。在460-495 nm的弱谱, 428-452 nm的六条谱带和385-398 nm之间的四条谱带, 则分别认证为相应于经历了B, C和D态的(3+1)MPI光谱。求得B态的项值T_0≤60729 cm~(-1), D态的T_0≤75567 cm~(-1), 而D态的反演振动频率ω_2为510 cm~(-1).

THE UV PHOTOLYSIS AND MULTIPHOTON IONIZATION OF HYDRIDES OF GROUP VA ELEMENTS (Ⅱ)

Using an excimer pumped dye laser system, the multiphoton ionization MPI spectrum PH_3 was investigated between 300-640 nm. More than 20 bands have been recorded and a primary assignment has been made. Near 20 bands observed in the range of 351-398 nm (Fig.3) are suggested to be a (2+1) excitation via PH_3 (Ã) state which was continuum observed in the absorption spectra. However, an estimated lifetime of 5×10~(-13) s for PH_3 (Ã) state still allows a subseqent excitation with a rate of 10~(12) s~(-1). The spectral bands of (Ã←X) exhib and an average interval of 263 cm~(-1).Some weak bands between 460—495 nm are asigned to be (3+1) ionization via B state. A new formula [Formula (2)] modifies the original one which was suggested by Humphiries et al.~[1].Six bands in 428—452 nm and four bands in 385—398 nm are assigned to the (3+1) MPI spectra via C and D states respectively. The term value of D state is estimated to be≤75567 cm~(-1), and ω_0 is about 510 cm~(-1).