A deperturbation analysis of the B 3Σ u −( v ′=0–6) and th B ″ 3Π u ( v ′=2–12) states of S2
1996; American Institute of Physics; Volume: 104; Issue: 3 Linguagem: Inglês
10.1063/1.470810
ISSN1520-9032
AutoresM. E. Green, Colin M. Western,
Tópico(s)Spectroscopy and Laser Applications
ResumoLaser-induced fluorescence spectra of 32S2 have been obtained, covering v′=0–6 of the B 3Σ−u–X 3Σ−g transition and v′=2–12 of the B″ 3Πu–X 3Σ−g transition, using static cell and supersonic free jet techniques. The spectra include transitions to the previously unseen B″ 3Π2,u components. Analysis of the many perturbations between the two upper electronic states has been carried out using a Hamiltonian matrix including all the B and B″ states simultaneously rather than deperturbing individual pairs of vibronic states. This takes into account longer range interactions and gives deperturbed molecular constants that vary smoothly with vibrational state. Our model for the B″ v′=2–12 and B v′=0–6 levels covering J up to 100 can fit all 3320 observed transitions with an average error of 0.064 cm−1. The widely ranging fluorescence lifetimes of the B″ state vibronic levels provide independent information about the state mixing and confirm the model, since the observed B″–X fluorescence arises almost entirely via this mixing. However, lifetime measurements of the newly observed Ω=2 components of the B″ state showed little variation in lifetimes, about an average of 4.2±0.4 μs. This indicates a small intrinsic B″–X transition strength as the Ω=2 components are essentially not mixed with the B state. A model for the perturbation parameters is developed, based on Franck–Condon factors between the two states. The magnitude of the perturbations and transition moments are discussed in relation to the electronic configurations of the B and B″ states.
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