Theoretical investigation of the enhancement of positron affinity by the vibration and dimerization of non-polar carbon disulfide
Theoretical investigation of the enhancement of positron affinity by the vibration and dimerization of non-polar carbon disulfide
复制标题
非极性二硫化碳振动和二聚增强正电子亲和力的理论研究
DOI：
10.1039/d1cp02808a
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发表时间：
2021
影响因子：
3.3
通讯作者：
Tachikawa Masanori
中科院分区：
文献类型：
--
作者：
Furushima Miku;Yoshida Daisuke;Kita Yukiumi;Shimazaki Tomomi;Tachikawa Masanori
非极性二硫化碳（CS2）的正电子结合态已被实验确定，虽然以前的理论研究，这是专门研究的正电子CS2单体，不能合理地重现实验测量的正电子亲和力。在本研究中，我们进行了分析的振动平均正电子亲合能的正电子CS2二聚体，[C2 S4; e+]，使用Hartree-Fock和组态相互作用水平的多组分分子轨道方法结合振动变分Monte Carlo方法的自洽场水平。我们证明了非极性C2 S4的平衡结构可以具有正电子束缚态，在组态相互作用水平下的正电子亲和力约为46.18 meV，而在Hartree-Fock水平下为0 meV。此外，通过考虑振动效应，我们成功地再现了共振正电子动能躺在接近实验值，其中的振动平均正电子亲和势变得更大的偶极矩和偶极极化率的增加。我们还展示了有效增强[C2 S4; e+]共振正电子捕获的可能机制，与红外活性和红外非活性振动模式相关。
The positronic bound state for the non-polar carbon disulfide (CS2) has been experimentally identified, although previous theoretical investigations, which were dedicated to studying the positronic CS2 monomer, could not reasonably reproduce the experimentally measured positron affinity. In the present study, we performed analysis of the vibrational averaged positron affinity for the positronic CS2 dimer, [C2S4; e+], using the Hartree–Fock and configuration interaction levels of the multi-component molecular orbital method combined with the self-consistent field level of the vibrational variational Monte Carlo method. We demonstrated that the equilibrium structure of the non-polar C2S4 can have the positronic bound state with a positron affinity of about 46.18 meV in the configuration interaction level, while this is 0 meV in the Hartree–Fock level. Furthermore, by taking into account the vibrational effect, we succeeded in reproducing the resonant positron kinetic energies lying close to the experimental value, where the vibrational averaged positron affinity becomes greater with an increased dipole moment and dipole polarizability. We also showed possible mechanisms to effectively enhance the resonant positron capture for [C2S4; e+], associated with both the infrared active and infrared inactive vibrational modes.