Third-order Douglas-Kroll relativistic coupled-cluster theory through connected single, double, triple, and quadruple substitutions: applications to diatomic and triatomic hydrides.
Third-order Douglas-Kroll relativistic coupled-cluster theory through connected single, double, triple, and quadruple substitutions: applications to diatomic and triatomic hydrides.
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DOI：
10.1063/1.1639361
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发表时间：
2004-02
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影响因子：
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通讯作者：
S. Hirata;Takeshi Yanai;W. D. de Jong;T. Nakajima;K. Hirao
中科院分区：
文献类型：
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作者：
S. Hirata;Takeshi Yanai;W. D. de Jong;T. Nakajima;K. Hirao
耦合集群的方法，包括通过和高达连接的单，双，三重，和四重取代已被推导和自动执行的顺序和并行执行的代数和符号操作程序TCE（张量膨胀引擎）结合使用的一个组件的三阶道格拉斯-克罗尔近似相对论修正。结合会聚电子相关方法、精确的相对论参考波函数和使用适合于相对论近似的系统基组，已被证明可以预测实验单重态-三重态分离在0.02eV以内（0.5 kcal/mol），对于5个三原子团（CH 2，NH 2+，SiH 2，PH 2+和AsH 2+），实验键长（re或r 0）在0.002埃内，旋转常数（Be或B 0）在0.02 cm（-1）以内，振动-旋转常数（α e）在0.01 cm（-1）以内，离心畸变常数（De）在2%以内，8 cm（-1）范围内的谐波振动频率（Ω）（0.4%），非谐振动常数（xomegae）在2cm（-1）以内，解离能（D 0（0））在0.02eV以内（0.4 kcal/mol），对于包含周期表第二至第五行的主族元素的二十个双原子簇（BH、CH、NH、OH、FH、AlH、SiH、PH、SH、ClH、GaH、GeH、AsH、SeH、BrH、InH、SnH、SbH、TeH和IH）。在这些计算中，从原子和双原子分子的测量的自旋-轨道耦合常数估计了对解离能的自旋-轨道效应，假定其是加性的，并且以两种方式外推了完整基组、完整电子相关极限中的电子能量，以验证结果的稳健性：一个假设的高斯指数依赖的总能量的两倍到四倍zeta基组和其他假设的n（-3）依赖的相关能量的两倍到五倍zeta基组。
Coupled-cluster methods including through and up to the connected single, double, triple, and quadruple substitutions have been derived and implemented automatically for sequential and parallel executions by an algebraic and symbolic manipulation program TCE (TENSOR CONTRACTION ENGINE) for use in conjunction with a one-component third-order Douglas-Kroll approximation for relativistic corrections. A combination of the converging electron-correlation methods, the accurate relativistic reference wave functions, and the use of systematic basis sets tailored to the relativistic approximation has been shown to predict the experimental singlet-triplet separations within 0.02 eV (0.5 kcal/mol) for five triatomic hydrides (CH2, NH2+, SiH2, PH2+, and AsH2+), the experimental bond lengths (re or r0) within 0.002 angstroms, rotational constants (Be or B0) within 0.02 cm(-1), vibration-rotation constants (alphae) within 0.01 cm(-1), centrifugal distortion constants (De) within 2%, harmonic vibration frequencies (omegae) within 8 cm(-1) (0.4%), anharmonic vibrational constants (xomegae) within 2 cm(-1), and dissociation energies (D0(0)) within 0.02 eV (0.4 kcal/mol) for twenty diatomic hydrides (BH, CH, NH, OH, FH, AlH, SiH, PH, SH, ClH, GaH, GeH, AsH, SeH, BrH, InH, SnH, SbH, TeH, and IH) containing main-group elements across the second through fifth rows of the periodic table. In these calculations, spin-orbit effects on dissociation energies, which were assumed to be additive, were estimated from the measured spin-orbit coupling constants of atoms and diatomic molecules, and an electronic energy in the complete-basis-set, complete-electron-correlation limit has been extrapolated in two ways to verify the robustness of the results: One assuming Gaussian-exponential dependence of total energies on double through quadruple zeta basis sets and the other assuming n(-3) dependence of correlation energies on double through quintuple zeta basis sets.