外电场作用下D-甘油酸分子的结构和光谱研究

Molecular structure and electronic spectrum of D-glyceric acid under external electric field

采用密度泛函(DFT)B3LYP方法在6-311G基组上优化了不同外电场作用下D-甘油酸分子的基态几何结构、电偶极矩和分子的总能量,并在此基础上利用含时密度泛函(TD-DFT)方法在相同基组下探讨了各电场情况下D-甘油酸分子前6个激发态的激发能、波长和振子强度与外电场大小的关系.结果表明:分子的几何构型在外电场F=0.003 a.u.时会发生明显的变化,当外电场强度F=0.003 a.u.时,分子总能量骤然下降,电偶极矩骤然上升,其紫外吸收峰也出现明显的红移.当电场继续增加时,上述指标重新回到正常水平,骤变消失.

The ground states of D-glyceric acid under different intense electric fields are optimized by using density functional theory DFT/B3LYP at 6-311G basis set level.The excitation energies and oscillator strength under the applied electric fields are calculated employing TD-DFT method.The results reveal the variations of electronic state,molecular geometry,total energy,dipolemoment,and excitation energy of the first six excited states with the applied electric field.Moreover,the results show that the set of molecular structures have changed obviously in the external electric field when the electric field strength is 0.003 a.u.,characterized by the decrease of molecular total energy,the sudden rise of dipolemoment,and an obvious red shift in UV-Vis spectra peak.When the electric field continues to increase,the indices return to normal levels and the sudden changes disappear.