The third-order non-Dyson algebraic-diagrammatic construction approach to the electron propagator [IP-ADC(3)] is extended using the intermediate state representation (ISR) formalism, allowing the wave functions and properties of molecular states with detached electron to be studied. The second-order ISR equations [ISR(2)] for the one-particle (transition) density matrix have been derived and implemented in the Q-CHEM program. The approach is completely general and enables evaluation of arbitrary one-particle operators and interpretation of electron detachment processes in terms of density-based quantities. The IP-ADC(3)/ISR(2) equations were implemented for Ŝz-adapted intermediate states, allowing open-shell molecules to be studied using unrestricted Hartree-Fock references. As a first test for computations of ground state properties, dipole moments of various closed- and open-shell molecules have been computed by means of electron detachment from the corresponding anions. The results are in good agreement with experimental data. The potential of IP-ADC(3)/ISR(2) for the interpretation of photoelectron spectra is demonstrated for the galvinoxyl free radical.

中文翻译：

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中间态表示方法用于分子电子离解态的物理性质。一，理论与实施。

电子传播器[IP-ADC（3）]的三阶非Dyson代数图解法构造方法使用中间态表示（ISR）形式主义进行了扩展，从而使电子的波函数和分子态的性质得以分离研究。一粒子（跃迁）密度矩阵的二阶ISR方程[ISR（2）]已导出并在Q-CHEM程序中实现。该方法是完全通用的，并且可以评估基于密度的量的任意单粒子算子并解释电子脱离过程。IP-ADC（3）/ ISR（2）方程用于Ŝz适应的中间态，允许使用不受限制的Hartree-Fock引用来研究开壳分子。作为计算基态特性的第一个测试，通过与相应阴离子的电子离解，已计算出各种闭壳和开壳分子的偶极矩。结果与实验数据吻合良好。galvinoxyl自由基证明了IP-ADC（3）/ ISR（2）解释光电子能谱的潜力。