Two-photon dissociation dynamics of the mercapto radical
Two-photon dissociation dynamics of the mercapto radical
复制标题
巯基自由基的双光子解离动力学
DOI：
10.1039/d2cp04116b
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发表时间：
2022
影响因子：
3.3
通讯作者：
Zhang, Jingsong
中科院分区：
文献类型：
--
作者：
Qin, Yuan;Zheng, Xianfeng;Song, Yu;Sun, Ge;Zhang, Jingsong
使用高 n 里德堡原子飞行时间 (HRTOF) 技术研究了 SH/SD 自由基的双光子解离动力学。 H/D(2S) + S(1D) 和 H/D(2S) + S(1S) 产物在 22Π 和 B2Σ+ 排斥态上的 SH/SD 自由基解离中观察到，来自通过 A2Σ+ (v′ = 0, J′ = 0.5–2.5) 态的连续双光子激发。 H/D(2S) + S(1D) 和 H/D(2S) + S(1S) 产物通道的角度分布都是各向异性的。 H(2S) + S(1D) 产品的各向异性参数 (β) 为 ∼−0.8 ± 0.1（SD 为 −0.9 ± 0.05），H(2S) + S(1S) 产品的各向异性参数为 ∼1.3 ± 0.3（SD 为 1.2）。各向异性角分布表明，SH/SD 自由基在排斥性 22Π 和 B2Σ+ 势能曲线 (PEC) 上迅速解离以及一些非绝热交叉，分别产生 H/D(2S) + S(1D) 和 H/D(2S) + S(1S) 产物。基态 X2Π3/2 SH/SD 与基态 H/D(2S) + S(3P2) 产物的键解离能分别测量为 D0(S–H) = 29 253 ± 20 cm−1 和 D0(S–D) = 29 650 ± 20 cm−1。 A2Σ+ 态 SH/SD 到 H/D(2S) + S(1D) 产物的解离能为 D0[S–H(A)] = 7659 ± 20 cm−1 和 D0[S–D(A)] = 7940 ± 20 cm−1。
Two-photon dissociation dynamics of the SH/SD radicals are investigated using the high-n Rydberg atom time-of-flight (HRTOF) technique. The H/D(2S) + S(1D) and H/D(2S) + S(1S) products are observed in the dissociation of the SH/SD radicals on the 22Π and B2Σ+ repulsive states, from sequential two-photon excitation via the A2Σ+ (v′ = 0, J′ = 0.5–2.5) state. The angular distributions of both H/D(2S) + S(1D) and H/D(2S) + S(1S) product channels are anisotropic. The anisotropy parameter (β) of the H(2S) + S(1D) products is ∼−0.8 ± 0.1 (−0.9 ± 0.05 for SD), and that of the H(2S) + S(1S) products is ∼1.3 ± 0.3 (1.2 for SD). The anisotropic angular distributions indicate that the SH/SD radicals promptly dissociate on the repulsive 22Π and B2Σ+ potential energy curves (PECs) along with some non-adiabatic crossings, leading to the H/D(2S) + S(1D) and H/D(2S) + S(1S) products, respectively. The bond dissociation energy of the ground-state X2Π3/2 SH/SD to the ground-state H/D(2S) + S(3P2) products is measured to be D0(S–H) = 29 253 ± 20 cm−1 and D0(S–D) = 29 650 ± 20 cm−1, respectively. The dissociation energy of the A2Σ+ state SH/SD to the H/D(2S) + S(1D) products is derived to be D0[S–H(A)] = 7659 ± 20 cm−1 and D0[S–D(A)] = 7940 ± 20 cm−1.