中文摘要：

在超声射流条件下得到了1-甲基萘的激光诱导荧光光谱,并结合理论计算研究了1-甲基萘分子的基态和激发态的几何构型及振动信息。运用DFT方法在B3LYP/6-311＋＋G＊＊的水平上优化了1-甲基萘的基态几何构型,结果表明1-甲基萘分子基态的S-E和E-S两个构象体中,只有S-E构象体为稳定构型,E-S构象是连接两个S-E构象的过渡态。采用CIS方法对S-E构象体的激发态进行了结构优化及振动分析,用计算得到的激发态振动频率以及TDDFT方法计算的垂直激发能对1-甲基萘的荧光光谱进行了分析与标识。研究结果表明,1-甲基萘的S0→S1的跃迁强度比萘的相应跃迁有所增强,但是依然存在与更高激发态之间的Herzberg-Teller耦合效应。

英文摘要：

Laser-induced fluorescence excitation spectrum of S0→S1 transition of 1-methylnaphthalene was obtained in supersonic jet condition.Theoretical calculations were conducted to study the geometry and energy of 1-methylnaphthalene at the ground and first excited state.Geometry optimization for the ground state was performed by DFT/B3LYP methods using 6-311＋＋G（d,p） basis set.CIS/6-311＋＋G（d,p） method was used to study the excited state.The excitation spectrum of 1-methylnaphthalene was assigned with the help of calculated vibrational frequencies and vertical excitation energies predicted by TDDFT method.It was found that the oscillator strength of the S0→S1 transition was enhanced by substituting a hydrogen atom of naphthalene with the methyl group although the Herzberg-Teller vibronic coupling effect still existed.