In this work,we investigate the performance of various equation-of-motion/linear-response coupled cluster(EOM/LR-CC)methods with an approximate treatment for triples on excitation energies(EEs)by comparing with EOM-CC...In this work,we investigate the performance of various equation-of-motion/linear-response coupled cluster(EOM/LR-CC)methods with an approximate treatment for triples on excitation energies(EEs)by comparing with EOM-CCSDT(SDT=single,double,triple excitations)results.The focus of this work is on singly-excited states with percentages of the single excitation part(R_(1),%)from CC3 between 50%and 80%,i.e.,excited states with a pronounced double excitation character.CC3 is shown to provide EEs that agree well with EOM-CCSDT results for such excited states.Moreover,reliable EEs can be obtained with EOM-CCSD(T)(a)^(*) and CCSDR(3)for excited states with R1 from CC3 larger than 80%.As for singly-excited states with R1 from CC3 between 80%and 50%,EEs with EOM-CCSD^(*),CCSDR(T)andδ-CR-EOM-CC(2,3)-D agree reasonably well with those of EOM-CCSDT.However,it is too costly to choose a proper method for singly-excited states based on R_(1) of CC3 since CC3 is a rather expensive method.On the other hand,our results show that difference between EEs with EOM-CCSD and EOM-CCSD(T)(a)*[ΔE_((T)(a)*)]correlates well with R1 from CC3 andΔE_((T)(a)*)is about 0.25 eV when R_(1)(CC3)is 80%.Appropriate methods to obtain reasonable EEs for singly-excited state can be chosen based on whetherΔE_((T)(a)*)is larger than 0.25 eV.展开更多
The ground state of osmium monoxide(OsO) has long been controversial. In this paper, the low-lying Λ–S and ? electronic states of OsO have been comprehensively studied by the high-precision multi-reference calculati...The ground state of osmium monoxide(OsO) has long been controversial. In this paper, the low-lying Λ–S and ? electronic states of OsO have been comprehensively studied by the high-precision multi-reference calculations. The ground state of OsO is unexpectedly the closed-shell1Σ+state with a double bond instead of the previously reported3Φ or5Σ+state;after including the spin–orbit coupling effects, the ground state becomes3Π2. With the help of the theoretical spectroscopic constants and transition dipole moments, the emission spectra in the region of 405 nm–875 nm are assigned.Our results will facilitate the future studies of absorption and emission spectra of OsO.展开更多
The Hückel’s rule,Baird’s rule,and electronic shell closure model are classical and well-established concepts in chemistry,which have long been employed in rationalizing the aromaticity/antiaromaticity of organ...The Hückel’s rule,Baird’s rule,and electronic shell closure model are classical and well-established concepts in chemistry,which have long been employed in rationalizing the aromaticity/antiaromaticity of organic species and stability of inorganic clusters.Thus,the observation of unique species featuring properties out of the fundamental frameworks of these rules is challenging but significant and helps in drawing a complete picture of fascinating concepts in chemistry.展开更多
基金supported by the National Natural Science Foundation of China(Nos.21973063,21773160)。
文摘In this work,we investigate the performance of various equation-of-motion/linear-response coupled cluster(EOM/LR-CC)methods with an approximate treatment for triples on excitation energies(EEs)by comparing with EOM-CCSDT(SDT=single,double,triple excitations)results.The focus of this work is on singly-excited states with percentages of the single excitation part(R_(1),%)from CC3 between 50%and 80%,i.e.,excited states with a pronounced double excitation character.CC3 is shown to provide EEs that agree well with EOM-CCSDT results for such excited states.Moreover,reliable EEs can be obtained with EOM-CCSD(T)(a)^(*) and CCSDR(3)for excited states with R1 from CC3 larger than 80%.As for singly-excited states with R1 from CC3 between 80%and 50%,EEs with EOM-CCSD^(*),CCSDR(T)andδ-CR-EOM-CC(2,3)-D agree reasonably well with those of EOM-CCSDT.However,it is too costly to choose a proper method for singly-excited states based on R_(1) of CC3 since CC3 is a rather expensive method.On the other hand,our results show that difference between EEs with EOM-CCSD and EOM-CCSD(T)(a)*[ΔE_((T)(a)*)]correlates well with R1 from CC3 andΔE_((T)(a)*)is about 0.25 eV when R_(1)(CC3)is 80%.Appropriate methods to obtain reasonable EEs for singly-excited state can be chosen based on whetherΔE_((T)(a)*)is larger than 0.25 eV.
基金Project supported by the National Natural Science Foundation of China (Grant No. 22073072)the Double First-Class University Construction Project of Northwest University。
文摘The ground state of osmium monoxide(OsO) has long been controversial. In this paper, the low-lying Λ–S and ? electronic states of OsO have been comprehensively studied by the high-precision multi-reference calculations. The ground state of OsO is unexpectedly the closed-shell1Σ+state with a double bond instead of the previously reported3Φ or5Σ+state;after including the spin–orbit coupling effects, the ground state becomes3Π2. With the help of the theoretical spectroscopic constants and transition dipole moments, the emission spectra in the region of 405 nm–875 nm are assigned.Our results will facilitate the future studies of absorption and emission spectra of OsO.
基金supported by the Start-up Funds of Xi'an Polytechnic University,China(BS1211)Scientific Research Program Funded by Shaanxi Provincial Education Department,China(2013JK0679)~~
基金supported by the Taishan Scholars Project of Shandong Province(no.ts201712011)the National Natural Science Foundation of China(NSFC)(nos.21603119 and 21705093)+4 种基金the Natural Science Foundation of Shandong Province(nos.ZR2017BB061 and ZR2016BQ09)the Natural Science Foundation of Jiangsu Province(no.BK20170396)the Project for Scientific Research Innovation Team of Young Scholar in Colleges and Universities of Shandong Province(no.2019KJC025)the Young Scholars Program of Shandong University(YSPSDU)(no.2018WLJH48)the Qilu Youth Scholar Funding of Shandong University,and the Fundamental Research Funds of Shandong University(no.2017TB003).
文摘The Hückel’s rule,Baird’s rule,and electronic shell closure model are classical and well-established concepts in chemistry,which have long been employed in rationalizing the aromaticity/antiaromaticity of organic species and stability of inorganic clusters.Thus,the observation of unique species featuring properties out of the fundamental frameworks of these rules is challenging but significant and helps in drawing a complete picture of fascinating concepts in chemistry.
