氯化氢共振多光子电离光谱:F^1△_2态的光谱微扰分析

Resonance enhanced multiphoton ionization spectra of HCl: analysis of F^1△_2 spectral perturbation

通过共振多光子电离-飞行时间法,记录了氯化氢分子在84800—85700cm-1范围内,F1△2(v′=1)里德堡态以及V1Σ+(v′=13,14)离子对态的电离产物H+,35Cl+,H35Cl+及其同位素的光谱数据.由于受离子对态V1Σ+的作用,F1△2(v′=1)态呈现出明显的近共振相互作用特性.为了分析F1△2与V1Σ+态之间存在的光谱微扰,基于光解离电离通道的分析,并针对F1△2(v′=1)态离子信号比的变化,将离子信号二能级作用模型优化到三能级的作用模型,计算得到了微扰强度值为0.6cm-1,预解离系数γ为0.025.此外,对于F1△2(v′=1)与V1Σ+(v′=13,14)态的三个振动能级的光谱峰位置,采用光谱解微扰法拟合,同样得到了类似的微扰强度和去微扰后的各光谱参数.研究表明,激发至F1△2(v′=1)态得到的H+,Cl+离子主要是该态通过与离子对态耦合作用而产生,而F1△2(v′=1)态光谱位置偏移不仅受离子对态而且还受其他里德堡态作用的影响.同时,非零γ值证实了F1△2态预解离的存在.

Spectra of H＋, 35Cl＋, H35Cl＋ and their isotopologues, due to resonance enhanced multiphoton ionization （REMPI） of HCl via the F1△2 （v＇ = 1） Rydberg and V1∑＋ （v＇ = 13, 14） ion-pair states are recorded in a range of 84800-85700 cm-1. Perturbation effects indicate the resonance interaction between the F1△2 （v＇ = 1） and V1∑＋ （v＇ = 14） states. An improved model for analyzing relative signal intensity of spectrum, based on state interaction and photofragmentation process, is used to analyze the F1△2 （v＇ = 1） spectral data. Interaction strength （W＇ = 0.6 cm-1） and a predissociation parameter （y = 0,025） are derived. Comparable interaction strength and unperturbed spectroscopic parameters are derived from the deperturbation analysis of line positions for the F1△2 （v＇ = 1） and V 1∑＋ （v＇ = 13, 14） spectra. The study indicates that the formation of the H＋ and C1~ ions via two-photon resonance excitation of F 1△2 （v＇ = 1） state is associated with the state interaction. An indicatibn of the line-shift of F1△2 （v＇ = 1） state spectrum due to Rydberg-to- Rydberg state interaction is also found. The nonzero y value suggests that the predissociation of the F1△2 state is important.