对乙基苯酚是构成酪氨酸分子的重要基团,根据其光谱特性可以洞察酪氨酸的光学特性。我们采用超声分子束技术获得了对乙基苯酚的单色共振双光子电离光谱,首次报道了800~1 500 cm-1范围的高分辨率激发态振动谱。配合量子化学理论计算分析了各谱对应的振动模式。结果表明取代基越长,分子的激发能越低;取代基的方向对激发能有明显影响;取代基会使苯环平面内的振动能量降低,但取代链的长短对振动能量没有明确影响。研究结果为分子的里德堡态、动力学和零动能光谱的相关研究提供了重要的参考数据。

p-ethylphenol is a base molecule of tyrosine which is an important amino acid. Detailed spectroscopic data on p-ethylphenol can help us to have better insights into the photochemical and photophysical properties of tyrosine. We used supersonic molecular beam technique to obtain one-color resonant two-photon ionization spectra of p-ethylphenol. The high-resolution vibrational spectra between 8 00~1 500 cm-1 in the excited state were first reported. The experimental findings were supported by ab initio and density functional theory calculations.Its results showed that the longer the substituent was,the lower the excitation energy of the molecule was.The relative direction of the substituent had a significant effect on the excitation energy.Substituted group made the in-plane vibration energies decrease,but substituted group chain length has no definite effect on the vibrational energy. These results provide essential information for the researches of molecular Rydberg states,dynamics and zero kinetic energy spectroscopy.