外电场下TCNQ的激发与光谱性质研究

The excited states structure and spectroscopy for tetracyanoquinodime thane(TCNQ) under the external electric Field

采用密度泛函B3PLY方法优化了不同外电场下TCNQ分子的基态稳定构型、电偶极矩和分子的总能量,并且分析了TCNQ分子的HOMO-2到LUMO+2轨道的能量变化.然后利用杂化CIS-DFT方法在同样的基组下计算了外电场下TCNQ分子的前9个激发态的激发能、波长和振子强度,结果表明在没有外电场的情况下,TCNQ分子只有一个激发态能够激发,从基态跃迁到第1激发态.在有外电场的作用下,总能量随外电场的增加而逐渐减少,偶极矩随外电场的增加而不断增加.其前线轨道的能量也随外电场的增加不断减少,轨道分布也受外电场很大的影响.另外,外电场对TCNQ分子的激发波长也产生了一定影响.

The ground states parameters, dipole moment, charge distribution and the energies of MOs of TCNQ under different intense electric fields are optimized using density functional theory （DFT）B3PLY based on the 6-311 ＋ ＋ G＊＊ basis set level. The excitation energy, wavelength, oscillator strengths from ground state to the first nine different excited states are calculated employing the revised hybrid CISDFT method （CIS-B3PLY） under external electric fields, The results show that the TCNQ has only one excited state from ground state to the first excited state without external electric fields, the energy are proved decreasing with the increasing of external fields, but the dipole moment is contrary. The energies of MOs decreased with the increasing of external fields and orbital electron distribution were great influence of the external fields. Other, the electric fields have some effect on the wavelengths of TCNQ.