研究目的
Investigating the accuracy and efficiency of the third-order unitary coupled-cluster scheme (UCC3) and its second-order variant (UCC2) for the calculation of excited electronic states and oscillator strengths.
研究成果
The UCC3 scheme provides accurate excitation energies and oscillator strengths for excited electronic states, with improvements over UCC2. However, its performance is similar to ADC(3), and further development is needed for application to larger systems.
研究不足
The UCC3 scheme, while accurate, does not significantly outperform ADC(3) for Jacquemin’s benchmark set and is limited by its computational cost for larger systems.
1：Experimental Design and Method Selection:
The UCC3 and UCC2 schemes were implemented and benchmarked against established benchmark sets for excitation energies and oscillator strengths.
2：Sample Selection and Data Sources:
Calculations were performed for 134 excited singlet and 71 excited triplet states of 28 small to medium-sized organic molecules from Thiel’s benchmark set and Jacquemin’s benchmark set.
3：List of Experimental Equipment and Materials:
The calculations were carried out using a development version of the adcman module in the Q-Chem
4：2 program package. Experimental Procedures and Operational Workflow:
The UCC amplitude equations were solved iteratively, and the Hermitian secular problem was solved using the Davidson algorithm.
5：Data Analysis Methods:
Statistical error analysis was performed to compare the calculated excitation energies and oscillator strengths with theoretical best estimates.
独家科研数据包，助您复现前沿成果，加速创新突破
获取完整内容
