Resonance-Enhanced Multiphoton Ionization of CH2Br2: Rydberg States, Photofragmentation, and CH Spectra

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• 作者：Jingming Long ; Huasheng Wang ; 脕g煤st Kvaran
• 刊名：Journal of Physical Chemistry A
• 出版年：2014
• 出版时间：March 13, 2014
• 年：2014
• 卷：118
• 期：10
• 页码：1826-1831
• 全文大小：340K
• 年卷期：v.118,no.10(March 13, 2014)
• ISSN：1520-5215

文摘

Mass-resolved (2 + n) resonance-enhanced multiphoton ionization (REMPI) spectra of CH₂Br₂ in the two-photon resonance excitation region from 71鈥?00 to 82鈥?00 cm^鈥? were recorded and analyzed. Spectral structures allowed characterization of new molecular Rydberg states. C*(¹D₂) was found to be an important intermediate in the photodissociation processes. A broad spectral feature peaking at about 80鈥?63 cm^鈥? in the C⁺ spectrum and frequently seen in related studies is reinterpreted and associated with switching between three- and two-photon ionization of C*(¹D₂). Analysis of band structures due to transitions from the A²螖 state of CH* that were seen in the CH⁺ and C⁺ REMPI spectra allowed characterization of three electronic states of CH, assigned as E²螤, D²螤, and F²危⁺, which clarifies a long-term puzzle concerning the energetics of the CH radical. Predissociation of the E, D, and F states to form C*(¹D₂) occurs. Bromine atomic lines were observed and are believed to be associated with bromine atom formation via predissociation of CH₂Br₂ Rydberg states.