Characterization of light-induced potentials in the strong-field dissociation of O2+
Characterization of light-induced potentials in the strong-field dissociation of O2+
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DOI：
10.1103/physreva.102.053114
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发表时间：
2020-11-24
影响因子：
2.9
通讯作者：
Thumm, U.
中科院分区：
文献类型：
--
作者：
Abanador, P. M.;Thumm, U.
我们从理论上研究了光致电位（LIPs）对O-2+分子离子解离动力学的影响，这是在角分辨碎片动能释放（KER）光谱中观察到的。根据初始泵浦激光激发阳离子核波包的振动和旋转动力学，同时考虑到800 nm 40-fs探针激光脉冲中O-2+ (a（4)Pi(u)）和O-2+ (f（4)Pi(g)）电子态之间的偶极子耦合，峰值强度在10（13）和10(14)W/cm(2)之间，我们计算了角分辨KER谱，揭示了特征的能量和角依赖条纹结构。当分子取向角θ相对于探针脉冲偏振方向从0增加到pi/2时，这些条纹的能量向下移动。随着探针脉冲峰值强度的增大，KER条纹的角度相关位移增加，并与相关的Floquet键硬化井中振动谱的角度和光波强度相关，这是LIP在解离过程中瞬态O-2+核概率捕获的表现。通过研究在theta = pi/2处的LIP阳离子表面光诱导圆锥交点（LICI）附近的解离分子阳离子的旋转振动动力学，我们在KER光谱中识别出相关的角度依赖结构，提出了一种评估LICI在分子解离途径中的重要性的方法。
We investigate theoretically the imprints of light-induced potentials (LIPs) on the dissociation dynamics of O-2+ molecular ions, as observable in angle-resolved fragment kinetic-energy-release (KER) spectra. Following the vibrational and rotational dynamics of the initial pump-laser-excited cationic nuclear wave packet, while accounting for the dipole coupling between the O-2+ (a(4)Pi(u)) and O-2+ (f(4)Pi(g)) electronic states in 800-nm 40-fs probe-laser pulses with peak intensities between 10(13) and 10(14) W/cm(2), we calculate angle-resolved KER spectra which reveal characteristic energy- and angle-dependent fringe structures. These fringes shift downward in energy as the molecular alignment angle theta relative to the probe-pulse polarization direction increases from 0 to pi/2. The angle-dependent shifts in the KER fringes increase for larger probe-pulse peak intensities and follow the angle and light-wave-intensity dependence of the vibrational spectrum in the associated Floquet bond-hardening well, which is a manifestation of transient O-2+ nuclear-probability trapping in the LIP during dissociation. By examining the rovibrational dynamics of the dissociating molecular cation near the light-induced conical intersection (LICI) in the cationic LIP surface at theta = pi/2, we identify related angle-dependent structures in the KER spectra, suggesting a means for assessing the significance of LICIs in molecular dissociation pathways.