溶剂化对有机分子的紫外可见吸收光谱和荧光光谱的作用主要表现在对光谱的峰位置，峰形以及光谱强度的改变上，本论文使用平移谐振子近似下的弗兰克-康登（Franck-Condon）模拟联合极化连续介质模型（PCM）以及参数拟合来模拟咔唑(carbazole, CZ)和α-咔啉(α-carboline, AC)的在正己烷和乙腈溶液中的紫外可见吸收光谱和荧光光谱。我们应用DFT方法优化了CZ和AC的基态平衡几何构型，应用TDDFT方法优化了AC和CZ的两个最低激发单态的平衡几何构型并计算其频率。与此同时，我们应用PCM模型用相同的方法优化了分别在以正己烷和乙腈为溶剂的AC和CZ的基态和激发态平衡几何构型并计算其频率。通过对比AC和CZ分子各自基态和激发态的频率和转化矩阵，其差别比较小，可以使用平移谐振子模型。根据分子基态和激发态的平衡几何构型以及基态分子的转化矩阵，可以计算振动的Huang-Phys因子，进而模拟分子的光谱。此时，由于没有直接处理溶剂和溶质的相互作用，使用气相分子的几何构型模拟溶剂化光谱不是很理想，使用PCM模型计算得到的光谱可以表现出了一些溶剂化的影响，比气相计算所得光谱略有改进，但效果不大。此时，将溶剂对溶质分子的作用看作对溶质分子力常数的改变，由于分子的简正振动使用的是正则坐标，可以通过引入作用在原子质量上的参数来改变分子的力常数。变化了的力常数矩阵重新对角化可以得到新的振动频率。接下来，通过改变力常数来拟合光谱。我们对气相，以及PCM模型下的计算都采用了这种处理，CZ分子气相拟合得到了光谱相比之前有很大的改善，且CZ的PCM模型计算结合Franck-Condon拟合得到的光谱跟实验吻合的很好。而AC分子由于S0态和S1态的振动耦合比较强烈而只能改善其光谱，无法得到最优的参数组合。

The solvent effects on UV-Vis absorption spectra and fluorescence spectra are mainly showed in the modification of positions, intensities and shapes of the spectra band with the solute molecules in solvents of different polarity. In this thesis, we simulated the absorption spectra and fluorescence spectra of alpha-carboline (AC) and carbazole (CZ) in different solvent, n-hexane and acetonitrile. The Franck-Condon simulation of electronic spectra is used with displaced harmonic oscillator and scaling factors on the atom. The equilibrium geometries are calculated without and with polarizable continuum model (PCM) in solvent n-hexane and acetonitrile.The DFT method is used to calculate the equilibrium geometries of the ground state S0for AC and CZ without and with PCM, and the TDDFT method is used to calculate the equilibrium geometries of the first two singlet excited states S1 and S2 without and with PCM. The vibration analysis of every equilibrium geometry was done to ensure the geometry is a minimum, and to make sure it is reasonable to take the displaced harmonic oscillator model in the Franck-Condon simulation. We can compute the Huang-Physfactors of vibrations by using the geometries of ground state and a excited state and the Hessian matrix of the ground equilibrium geometry. The spectra simulated by using the geometries with PCM is better than that by using the geometries in gas phase, however, the former is still not good enough to show the solvent effects on spectra. The reason is that the direct solvent-solute interaction is not under consideration with the simulation we used. The forces on the solute by solvent can change the restoring force of the atoms in the solute molecule. We can treat it as constant scaling factors on the force constant. For the normal vibration is the function of normal coordination, and normal coordination is relative with the atom weight, if we make the scaling factors act on the atom weight, it is convenientto change the force constants. When the Hessian matrix is changed, we can easily obtain new vibrations and calculate the Huang-Rhys factors, and finally use the Franck-Condon simulation to get the spectra. The geometries in gas phase and with PCM were used with this method to simulate the spectra in solvent. The result spectra of CZ by using the geometries in gas phaseis much better than before, and the spectra by using the geometries with PCM can match the experiment data almost completely. However, for the strong coupling between the vibrations of S0 state and S1 state, we cannot obtain the experiment-liking spectra.