Quantum chemical calculations are performed using Gaussian16W Software to theoretically investigate the response of Li₂ molecule to external electric field. Ground state properties of Li₂ molecule in the presence of electric field are modelled using Density Functional Theory(CAM-B3LYP/[6-311++G(3df,3pd)]) while excited states are modelled using Symmetry Adapted Cluster Configuration Interaction theory and 6-311++G∗∗ basis set. The effect of external electric field on ground state properties including structural (bond length, total energy, harmonic vibrational frequency and rotational constant), electronic (dipole moment and polarizability) and thermodynamic (vibrational contribution to partition function, thermal energy, entropy and specific heat capacity) properties is reported. External electric field modifies the charge distribution within the molecule and hence its molecular properties. Potential energy curves and transition dipole moments of 22 states (13Singlet + 9Triplet) are also reported. The computed parameters agree well with the experimental data wherever the later is available.

使用Gaussian16W软件执行量子化学计算，以从理论上研究Li ₂分子对外部电场的响应。Li _2的基态性质使用密度泛函理论（CAM-B3LYP / [6-311 ++ G（3df，3pd）]）对存在电场的分子进行建模，而利用对称适应簇构型相互作用理论和6-311 ++对激发态进行建模G ∗∗基集。外部电场对基态特性的影响，包括结构（键长，总能量，谐波振动频率和旋转常数），电子（偶极矩和极化率）和热力学（振动对分配函数，热能，熵和比热的影响）容量）属性进行报告。外部电场会改变分子内的电荷分布，从而改变其分子特性。还报告了22种状态（13Singlet + 9Triplet）的势能曲线和跃迁偶极矩。