Mass-analyzed threshold ionization spectroscopy of trans-1-methoxynaphthalene cation and the methoxyl substitution effect

• Published in: Journal of molecular spectroscopy Vol. 284-285; pp. 16 - 20
• Main Authors: Shivatare, Vidya, Zheng, Qiusha, Zhang, Bing, Ganguly, Tapan, Tzeng, Wen Bih
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.02.2013
• Subjects: Cation spectroscopy; Resonant two-photon ionization; Threshold ionization; trans-1-Methoxynaphthalene; Cation spectroscopy; Threshold ionization; Resonant two-photon ionization; trans-1-Methoxynaphthalene
• ISSN: 0022-2852; 1096-083X
• DOI: 10.1016/j.jms.2013.02.001

[Display omitted] ► The MATI spectra of 1-methoxynaphthalene have been recorded. ► The adiabatic ionization energy has been determined to be 61357cm−1. ► Most of the observed cation vibrations result from the in-plane ring vibrations. ► The methoxyl substitution can affect transition energy and molecular vibrations. We applied the two-color resonant two-photon mass-analyzed threshold ionization technique to record the cation spectra of trans-1-methoxynaphthalene via five intermediate levels. The adiabatic ionization energy of this molecule is determined to be 61357±5cm−1, which is smaller than that of naphthalene by 4330cm−1. This indicates that the interaction between the OCH3 substituent and the aromatic ring is stronger in the cationic D0 state than that in the neutral S0 state. Comparing these data of trans-1-methoxynaphthalene with those of naphthalene, we find that the frequency difference of each mode depends on the vibrational pattern and the OCH3 group involved in the overall molecular motion.