Barborini Matteo, Guidoni Leonardo
Dipartimento di Ingegneria e Scienze dell'Informazione e Matematica, Università degli studi dell'Aquila , L'Aquila, Italy.
Dipartimento di Scienze Fisiche e Chimiche, Università degli studi dell'Aquila , , L'Aquila, Italy.
J Chem Theory Comput. 2015 Feb 10;11(2):508-17. doi: 10.1021/ct501157f. Epub 2015 Jan 30.
We investigate the effects of the static and dynamical electronic correlations on the level of conjugation of the trans-1,3-butadiene molecule through Quantum Monte Carlo methods applied to an Antisymmetrized Geminal Power (AGP) wave function, with a Jastrow factor similar to the Gutzwiller ansatz. The degree of conjugation is measured through the convergence of the structural properties of 1,3-butadiene and in particular of the Bond Length Alternation (BLA), that is the difference between the lengths of the single and double carbon bonds. After verifying the different roles of the Fermionic AGP part of our wave function and of the Jastrow factor in recovering electronic correlation, we study the effects of a constrained Active Space AGP (AGPAS), similar to that used in the Complete Active Space (CAS) representation. Through this AGPAS, we are able to identify the effect of the limited active space on the degree of conjugation, showing that in the limit of infinite active space the structural properties converge exactly to those of the atomic AGP, giving a BLA for 1,3-butadiene around 0.1244(5) Å.
我们通过应用于反对称双电子对幂（AGP）波函数的量子蒙特卡罗方法，研究了静态和动态电子关联对反式-1,3-丁二烯分子共轭水平的影响，该波函数具有与古兹维勒近似相似的雅斯特罗因子。共轭程度通过1,3-丁二烯结构性质的收敛来衡量，特别是键长交替（BLA），即单碳键和双碳键长度之间的差异。在验证了我们波函数的费米子AGP部分和雅斯特罗因子在恢复电子关联中的不同作用后，我们研究了受限活性空间AGP（AGPAS）的影响，它类似于完全活性空间（CAS）表示中使用的AGPAS。通过这种AGPAS，我们能够确定有限活性空间对共轭程度的影响，表明在无限活性空间的极限下，结构性质精确收敛到原子AGP的性质，1,3-丁二烯的BLA约为0.1244(5) Å。
