论文标题
通过其$ f \，^1π_U$ state
Multireference configuration interaction study of the predissociation of C$_{2}$ via its $F\,^1Π_u$ state
论文作者
论文摘要
光解离是在诸如弥散的星际云之类的天文环境中双核（c $ _ {2} $）的主要破坏途径之一，但是现代天体化学模型的准确性受到缺乏精确的光电消散横切的限制。 c $ _ {2} $具有强大的预生殖$ f \，^1π_u -x \，^1σ_g^+$ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $。但是，此后没有对该过渡进行实验研究，并且$ f \，^1π_U$状态的理论研究受到限制。在这项工作中，计算c $ _ {2} $激发电子状态的势能曲线的目的是描述$ f \，^1π_U$状态的前介质性质，并为天体化应用提供新的Af Af Af Af Af Af Af Af Af Af Af Af Af Af Af Af Af tim ibe。在DW-SA-CASSCF/MRCI+Q的理论水平上，使用CAS（8,12）活动空间（8,12）活性空间进行了56个单元，三重态和五重奏状态的精确电子计算，并使用其他扩散功能进行了增强。由振动基态态到$ f \，^1π_U$状态引起的光解离截面是由耦合通道模型计算得出的。 $ f \，^1π_U$ $ v = 0 $和$ v = 1 $ bands的总体集成横截面为1.198 $ \ times $ 10 $^{ - 13} $ cm $^2 $ cm $^2 $ cm $^{ - 1} $场，比Leiden光解离数据库中的速率大得多。此外，我们报告了一个新的$ 2 \，^1σ_U^+$状态，该状态应通过强$ 2 \，^1σ_U^+-x \，^1σ_g^+$ band Band在116 nm附近检测到。
Photodissociation is one of the main destruction pathways for dicarbon (C$_{2}$) in astronomical environments such as diffuse interstellar clouds, yet the accuracy of modern astrochemical models is limited by a lack of accurate photodissociation cross sections in the vacuum ultraviolet range. C$_{2}$ features a strong predissociative $F\,^1Π_u - X\,^1Σ_g^+$ electronic transition near 130 nm originally measured in 1969; however, no experimental studies of this transition have been carried out since, and theoretical studies of the $F\,^1Π_u$ state are limited. In this work, potential energy curves of excited electronic states of C$_{2}$ are calculated with the aim of describing the predissociative nature of the $F\,^1Π_u$ state and providing new ab initio photodissociation cross sections for astrochemical applications. Accurate electronic calculations of 56 singlet, triplet, and quintet states are carried out at the DW-SA-CASSCF/MRCI+Q level of theory with a CAS(8,12) active space and the aug-cc-pV5Z basis set augmented with additional diffuse functions. Photodissociation cross sections arising from the vibronic ground state to the $F\,^1Π_u$ state are calculated by a coupled-channel model. The total integrated cross section through the $F\,^1Π_u$ $v=0$ and $v=1$ bands is 1.198$\times$10$^{-13} $cm$^2$cm$^{-1}$, giving rise to a photodissociation rate of 5.02$\times$10$^{-10}$ s$^{-1}$ under the standard interstellar radiation field, much larger than the rate in the Leiden photodissociation database. In addition, we report a new $2\,^1Σ_u^+$ state that should be detectable via a strong $2\,^1Σ_u^+-X\,^1Σ_g^+$ band around 116 nm.
