标题： 甲基的激发态、多烯和臭氧的热浴组态相互作用 显示英文标题

标题： Excited States of Methylene, Polyenes, and Ozone from Heat-Bath Configuration Interaction

摘要： 甲基（CH$_2$）、乙烯（C$_2$H$_4$）、丁二烯（C$_4$H$_6$）、六三烯（C$_6$H$_8$）和臭氧（O$_3$）的电子激发态由于静态和动态相关性的复杂混合而长期以来一直具有挑战性。 半随机热浴配置相互作用(SHCI)，它能够高效且系统地逼近全组态相互作用(FCI)极限，被用来在这些系统中提供接近FCI能量的近似值。 本文介绍了迄今为止最大的FCI级计算——在六亚甲基使用极化双ζ基组(ANO-L-pVDZ)，这导致包含超过$10^{38}$个决定子的希尔伯特空间。 这些计算分别给出了$2^1{\rm A}_{\rm g}$和$1^1{\rm B}_{\rm u}$状态的垂直激发能为5.58和5.59 eV，表明它们几乎简并。 在丁二烯/ANO-L-pVDZ中的相同激发能分别为6.58和6.45 eV。 除了这些基准测试外，我们的计算强有力地支持了之前假设的臭氧环最小物种的存在，该物种比开环最小能量结构高1.3 eV，并且由1.11 eV的势垒与之分离。 显示英文摘要

摘要： The electronically excited states of methylene (CH$_2$), ethylene (C$_2$H$_4$), butadiene (C$_4$H$_6$), hexatriene (C$_6$H$_8$), and ozone (O$_3$) have long proven challenging due to their complex mixtures of static and dynamic correlations. Semistochastic heat-bath configuration interaction (SHCI), which efficiently and systematically approaches the full configuration interaction (FCI) limit, is used to provide close approximations to the FCI energies in these systems. This article presents the largest FCI-level calculation to date -- on hexatriene using a polarized double-zeta basis (ANO-L-pVDZ), which gives rise to a Hilbert space containing more than $10^{38}$ determinants. These calculations give vertical excitation energies of 5.58 and 5.59 eV respectively for the $2^1{\rm A}_{\rm g}$ and $1^1{\rm B}_{\rm u}$ states, showing that they are nearly degenerate. The same excitation energies in butadiene/ANO-L-pVDZ were found to be 6.58 and 6.45 eV. In addition to these benchmarks, our calculations strongly support the presence of a previously hypothesized ring-minimum species of ozone that lies 1.3 eV higher than the open-ring minimum energy structure and is separated from it by a barrier of 1.11 eV.