Cioslowski Jerzy, Matito Eduard
Institute of Physics, University of Szczecin , Wielkopolska 15, 70-451 Szczecin, Poland.
J Chem Theory Comput. 2011 Apr 12;7(4):915-20. doi: 10.1021/ct200053z. Epub 2011 Mar 9.
Full configuration interaction calculations carried out in conjunction with careful optimization of basis sets and judicious extrapolation schemes for 12 values of the confinement strength ω ranging from 0.1 to 1000.0 provide benchmark energies for the (2)P ground state and the (4)P first excited state of the three-electron harmonium atom, allowing for numerical verification of the recently obtained second-order energy coefficients and confirming the few available results of Monte Carlo studies. The final energy values, obtained by correcting the extrapolated data for residual errors in the low-order energy coefficients, possess accuracy of ca. 20 μHartree for the doublet state and ca. 10 μHartree for the quartet one, making them suitable for calibration and testing of approximate electron correlation methods of quantum chemistry. The energy limits for individual angular momenta ranging from 1 to 4 are also available, facilitating comparisons with results of calculations involving finite basis sets. An example of application involving the BLYP and B3LYP functionals is provided.
结合对基组的精心优化以及针对12个限制强度ω值（范围从0.1到1000.0）的明智外推方案进行的全组态相互作用计算，为三电子钬原子的(2)P基态和(4)P第一激发态提供了基准能量，从而能够对最近获得的二阶能量系数进行数值验证，并确认蒙特卡罗研究的少数可用结果。通过校正低阶能量系数中的残余误差而获得的最终能量值，对于双重态具有约20微哈特里的精度，对于四重态具有约10微哈特里的精度，使其适用于量子化学近似电子相关方法的校准和测试。还提供了从1到4的各个角动量的能量极限，便于与涉及有限基组的计算结果进行比较。给出了一个涉及BLYP和B3LYP泛函的应用示例。
