An attempt was made to determine the ground state and excited state dipole moments and quantum chemical computations of two coumarin compounds, namely 3‐hydroxy‐3‐[2‐oxo‐2‐(2‐oxo‐2H‐chromen‐3‐yl)‐ethyl]‐1,3‐dihydro‐indol‐2‐one (3HOCE) and 3‐[2‐(8‐methoxy‐2‐oxo‐2H‐chromen‐3‐yl)‐2‐oxo‐ethylidene]‐1,3‐dihydro‐indol‐2‐one (3MOCE). Both compounds displayed a red shift with enhancement in solvent polarity. The larger excited state dipole moment indicated the more polar nature of the selected compounds in the excited state than in the ground state. Kinetic stability and chemical reactivity of the selected compounds were studied with help of the quantum chemical properties of the compounds such as frontier molecular orbital analysis using density functional theory calculations with B3LYP/6–311+G (d, p) basis sets. Molecular electrostatic potential, Mulliken charges, natural bond orbital, and nonlinear optical properties were further studied. NBO analysis showed proton transfer within the selected donor–acceptor, depicting the large energy of stabilization for the compounds. The calculated Fukui function inferred the local softness and electrophilicity indices of used solute compounds.

中文翻译：

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两种香豆素化合物的量子化学计算和光物理光谱特征研究。

尝试确定两种香豆素化合物的基态和激发态偶极矩以及量子化学计算，即3-羟基-3- [2-氧代-2-（2-氧代-2H-铬n-3-基） -[乙基] -1,3-二氢吲哚-2-1（3HOCE）和3- [2-（8-甲氧基-2-氧代-2H-铬基-3-基）-2-氧代亚乙基] -1 ，3-二氢吲哚-2-一（3MOCE）。两种化合物均显示出红移，且溶剂极性增强。较大的激发态偶极矩表明，在激发态下比在基态下所选化合物的极性更大。借助化合物的量子化学特性，例如使用B3LYP / 6–311 + G（d，p）基组的密度泛函理论计算对前沿分子轨道进行分析，研究了所选化合物的动力学稳定性和化学反应性。分子静电势 进一步研究了Mulliken电荷，自然键轨道和非线性光学性质。NBO分析显示质子在选定的供体-受体内转移，说明化合物具有很大的稳定能量。计算得出的Fukui函数推断出所用溶质化合物的局部柔软度和亲电指数。