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参与光解离的二甲基二硫化物的兴奋状态电子结构在≤200 nm的光解离
Varun Rishi1, Neil C Cole-Filipiak1, Krupa Ramasesha1
1Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, USA. kramase@sandia.gov.
Physical chemistry chemical physics : PCCP
|September 6, 2024
概括
在使用先进的计算方法,研究了二甲基二硫化物 (DMDS) 在200nm的光碎片化. 扩展的多态CASPT2准确地模拟激发状态,揭示了对S-S和C-S债券分裂机制的洞察力.
科学领域:
- * 计算化学 计算机化学
- * 光化学 * 光化学
- * 分子光谱学
背景情况:
- *二甲基二硫化物 (DMDS) 是研究生物分子中的光碎片化的关键模型.
- *之前的研究集中在266nm和248nm的DMDS光解离,阐明了S-S和C-S键裂通过S1和S2状态.
- * 在~200nm激发的DMDS的电子结构和解离机制仍然不太清楚.
研究的目的:
- * 为了研究DMDS激发状态 (S1-S6) 的电子结构在~200 nm.
- * 为了阐明光碎裂机制和沿着S-S和C-S键解离坐标的潜在能量表面.
- * 评估用于描述复杂兴奋状态的计算方法的性能.
主要方法:
- * 计算激发状态S1-S6.6的电子结构和属性.
- * 沿着S-S和C-S键解离路径对一维潜在能量表面的理论预测.
- * 计算旋转轨道合常数以评估系统间交叉.
- * 扩展的多态完整活跃空间二阶扰动理论 (XMS-CASPT2) 和 EOM-CCSDT) 的应用和比较.
主要成果:
- * 电子状态S1-S6的识别在~200 nm访问.
- * 潜在能量表面的表征,揭示由于双倍激发和混合Rydberg-valence状态的挑战.
- *XMS-CASPT2展示了准确性和效率的平衡,捕捉了Rydberg和多配置字符.
- * EOM-CCSD ((T) ((a) *对双重兴奋状态显示出与 EOM-CCSD 相比的改善,但与非对称的能量作斗争.
结论:
- *XMS-CASPT2是一种适合研究在~200 nm的DMDS光片化的方法,可以准确地描述复杂的激发状态.
- *这项研究为DMDS在紫外线激发下电子结构和解离动态提供了关键的见解.
- * 了解这些机制对于解释较大的生物分子中的光解离至关重要.
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