Ross Andrew D, Hait Diptarka, Scutelnic Valeriu, Haugen Eric A, Ridente Enrico, Balkew Mikias B, Neumark Daniel M, Head-Gordon Martin, Leone Stephen R
Department of Chemistry, University of California Berkeley 94720 CA USA
Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley 94720 CA USA.
Chem Sci. 2022 Jul 19;13(32):9310-9320. doi: 10.1039/d2sc02402k. eCollection 2022 Aug 17.
X-ray Transient Absorption Spectroscopy (XTAS) and theoretical calculations are used to study CCl prepared by 800 nm strong-field ionization. XTAS simultaneously probes atoms at the carbon K-edge (280-300 eV) and chlorine L-edge (195-220 eV). Comparison of experiment to X-ray spectra computed by orbital-optimized density functional theory (OO-DFT) indicates that after ionization, CCl undergoes symmetry breaking driven by Jahn-Teller distortion away from the initial tetrahedral structure (T) in 6 ± 2 fs. The resultant symmetry-broken covalently bonded form subsequently separates to a noncovalently bound complex between CCl and Cl over 90 ± 10 fs, which is again predicted by theory. Finally, after more than 800 fs, L-edge signals for atomic Cl are observed, indicating dissociation to free CCl and Cl. The results for Jahn-Teller distortion to the symmetry-broken form of CCl and formation of the Cl-CCl complex characterize previously unobserved new species along the route to dissociation.
利用X射线瞬态吸收光谱(XTAS)和理论计算来研究通过800纳米强场电离制备的CCl。XTAS同时探测碳K边(280 - 300电子伏特)和氯L边(195 - 220电子伏特)处的原子。将实验结果与通过轨道优化密度泛函理论(OO-DFT)计算的X射线光谱进行比较表明,电离后,CCl在6 ± 2飞秒内通过 Jahn - Teller 畸变驱动远离初始四面体结构(T),发生对称性破缺。随后,形成的对称性破缺的共价键形式在90 ± 10飞秒内分离为CCl和Cl之间的非共价键结合复合物,这同样由理论预测。最后,在超过800飞秒后,观察到原子Cl的L边信号,表明解离为游离的CCl和Cl。CCl对称性破缺形式的 Jahn - Teller 畸变以及Cl - CCl复合物形成的结果表征了解离途径中以前未观察到的新物种。