尼古丁分子在有限对称外电场作用下的光激发特性

Photo Excitation Characteristics of Nicotine Molecules under Action of a Finite Symmetric External Electric Field

采用密度泛函B3P86和含时密度泛函理论(TD-DFT)方法,在6-311++G(2df)基组水平上计算尼古丁分子(C_(10)H_(14)N_2)第1至第10个激发态的激发能、波长和振子强度,并考察外电场对C_(10)H_(14)N_2分子激发态的影响规律.结果表明,在电场强度逐渐增加的过程中,最高占据分子轨道-最低未占分子轨道(HOMO-LUMO)之间的能隙呈逐渐减小趋势,C_(10)H_(14)N_2分子的激发能呈急剧减小趋势,即在外电场作用下,C_(10)H_(14)N_2分子易被激发和离解.

Using density functional B3P86 and time-dependent density functional theory （TD-DFT） methods, the author calculated the excitation energy, wavelengths and oscillator strength of C10 H14 N2 from ground state to tenth excited states at basis sets 6-311＋ ＋G（2df） level, and studied effect of external electric fields on the excited states of C10 H14 N2. The results show that the HOMO-LUMO gaps become smaller, and the excitation energies of the excited states of C10 H14 N2 decrease sharply as the external electric field intensity become strong. So the C10 H14 N2 molecules are easily excited and dissociated under the action of external electric field.