2-三氰基乙烯基蒽及其旋转异构体的量子化学研究

Quantum Chemistry Study on 2-Tricyanovinyl Anthracene and Its Rotamer

用量子化学从头算方法 ,在RHF/STO - 3G水平上 ,对 2_三氰基乙烯基蒽 (2_TCVA)分子进行了理论计算 ,优化得到了它的平衡几何构型 ,并计算了它的谐振动频率 .结果表明 :2_TCVA存在两种旋转异构体 :2_TCVA(1)和 2_TCVA(2 ) ,2_TCVA(2 )的总能量比 2_TCVA(1)的略高 .在PM3/CIS水平上计算了它们的电子光谱 ,得到了由基态到各激发态的垂直跃迁能和相应的振子强度 .研究表明 :2_TCVA(1)和 2_TCVA(2 )的强度最大的吸收波长分别为 2 4 9.72nm和 2 89.4 1nm ,2_TCVA(2 )的强度最大的吸收波长比 2_TCVA(1)的要长 .

Results of ab initio calculations are reported for 2_tricyanovinyl anthracene(2_TCVA) at RHF/STO_3G level, the equilibrium geometry of 2_TCVA has been optimized and the harmonic vibrational frequency has been calculated . The calculating results show that there are two form rotamer for 2_TCVA: 2_TCVA(1) and 2_TCVA(2), 2_ TCVA(2) is slightly higher than 2_TCVA(1) in total energy. At PM3/CIS level, the vertical excitation spectra were calculated and the vertical excitation energies and corresponding oscillator strength from the ground states to the excited states are obtained. The results reveal that the absorption wavelength of maximum oscillator strength for 2_TCVA(1) and 2_TCVA(2) is 249.72nm and 289.41nm respectively. 2_TCVA(2) is longer than 2_TCVA(1) in the absorption wavelength of maximum oscillator strength. These results are in good agreement with those obtained from experiments.