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Updated: Jun 10, 2026

Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization
Published on: August 6, 2018
Rotamers of o- and m-dimethoxybenzenes studied by mass-analyzed threshold ionization spectroscopy and theoretical
Shih Chang Yang1, Ssu Wei Huang, Wen Bih Tzeng
1Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, 1 Section 4, Roosevelt Road, Taipei 10617, Taiwan.
Abstract:
We applied two-color resonant two-photon mass-analyzed threshold ionization (MATI) spectroscopy to investigate the molecular properties of the selected rotamers of o-dimethoxybenzene (ODMB) and m-dimethoxybenzene (MDMB). The present experimental results show that only one stable configuration is involved in the photoexcitation and ionization processes of ODMB, as predicted by theoretical calculations. The adiabatic ionization energy (IE) of ODMB is measured to be 61 617 ± 5 cm(-1). In the case of MDMB, both our experimental and calculated results suggest that there are three stable rotamers coexisting in the sample. The adiabatic IEs of rotamers a, b, and c are determined to be 63 523 ± 5, 64 491 ± 5, and 63 758 ± 5 cm(-1). Analysis on the MATI spectra shows that most of the active cation vibrations of these isomeric species result from in-plane ring motions. In addition, different orientations of the two OCH(3) groups have little effect on these vibrations.
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