Resonance-enhanced two-photon ionization spectroscopy and theoretical calculations of 3,5-difluoroanisole and its Ar-containing complex

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• 作者：Lijuan Zhang ; Changwu Dong ; Min Cheng ; Lili Hu ; Yikui Du ; Qihe Zhu ; Cunhao Zhang
• 关键词：3 ; 5-Difluoroanisole ; R2PI ; Quantum chemical calculations ; Substitution effect ; Ar-containing complex
• 刊名：Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
• 出版年：2012
• 出版时间：October, 2012
• 年：2012
• 卷：96
• 期：Complete
• 页码：578-585
• 全文大小：747 K

文摘

The structure and vibrations of 3,5-difluoroanisole (3,5-DFA) in the first electronically excited (S₁) state were studied by mass-analyzed resonant two-photon ionization (R2PI) technique as well as the quantum chemical calculations. The ab initio and density functional theory (DFT) calculations reveal that only one structure is stable for each of the S₀, S₁, and D₀ states. In the one color R2PI spectrum, the band origin of the S₁ ¡û S₀ electronic transition (0⁰ band) of 3,5-DFA is found to be 37,595 ¡À 3 cm^?1. In the S₁ state, most of the bands observed are related to the in-plane ring deformation and out-of-plane bending vibrations. The adiabatic ionization energy (IE) of 3,5-DFA is determined to be 70,096 ¡À 15 cm^?1 by the two color R2PI technique, in agreement with the values predicted by the DFT approaches. The dihalogen-substitution effects on the molecular structure, vibrational frequencies, and electronic transition and ionization energies were discussed in detail. The van der Waals complex of 3,5-DFA with argon (3,5-DFA¡¤¡¤¡¤Ar) was also observed and studied. The 0⁰ band of 3,5-DFA¡¤¡¤¡¤Ar complex is red-shifted by about 9 cm^?1 with respect to that of 3,5-DFA. Both the experimental data and the calculated results indicate that the formation of 3,5-DFA¡¤¡¤¡¤Ar complex gives only a weak influence on the properties of 3,5-DFA moiety.