The influence of external electrical field (EF) over the trans and cis isomers of azobenzene is investigated upto molecular orbital level with the aid of density functional theory. The frontier molecular orbital analysis and electrostatic potential (ESP) mapping are used to figure out the response of the molecules (trans and cis isomers of azobenzene) to the applied EF. The variation in dipole moment gives the extent of polarization in the molecule due to EF. With the aid of natural bond orbital analysis (NBO) the possible charge transfer path through the molecule can be predicted. ESP and NBO analysis clearly shows that drastic charge redistribution takes place for the EF strength of 0.15 V/Å. Hence the EF strength above 0.15 V/Å can be considered as threshold filed strength for organic molecular conductance. All these theoretical investigations provide a basic knowledge about the influence of molecular conformation over the conductivity of a molecule in the presence of EF.

中文翻译：

---

通过偶氮苯的反式和顺式异构体分析电荷转移路径的 DFT 方法

借助密度泛函理论，研究了外部电场 (EF) 对偶氮苯的反式和顺式异构体的影响，直至分子轨道水平。前沿分子轨道分析和静电势 (ESP) 映射用于计算分子（偶氮苯的反式和顺式异构体）对应用 EF 的响应。由于 EF，偶极矩的变化给出了分子中极化的程度。借助自然键轨道分析 (NBO)，可以预测通过分子的可能的电荷转移路径。ESP 和 NBO 分析清楚地表明，对于 0.15 V/Å 的 EF 强度，会发生剧烈的电荷重新分布。因此，高于 0.15 V/Å 的 EF 强度可以被视为有机分子电导的阈值场强度。