High-resolution Doppler spectroscopy of light-dressed states of multi-electron molecules

为了阐明光缀饰态在强激光场中多电子分子动力学中的作用，<14>在795 nm和398 nm激光波长下，利用O^+碎片离子的动量成像图，研究了O2 ^+→O^++O在强激光场中的解离过程.协方差图测量进行高动量分辨率，安全地分配解离途径。从O^+离子相对于激光偏振方向的各向异性动量分布可以看出，O_2^+离子的电子态在解离过程中只通过平行跃迁耦合。用O_2^+在四重态流形上的光修饰势曲线的序贯耦合模型，一致地解释了O^+在795 nm和398 nm处的释放动能，并在300 nm ~ 700 nm光谱范围内，用配备增强型CCD相机的光谱仪测量了NO和O_2的色散荧光光谱。观测到的光谱显示出许多谱线，其中大部分被归属于较高电荷碎片离子的电子跃迁，如N^+、N^&lt;2+&gt;、O^+和O^&lt;2+&gt;。在<-1>409.24 nm处对N III 3^2P°→3^2S跃迁进行了高分辨率（102 cm^）测量。当激光偏振方向指向谱仪时，观测到的谱线呈现双峰模式，这是由于NO的库仑爆炸作用使N^2+碎片离子释放出大量动能的结果。根据谱线分裂模式估算的动能，发现N^2+碎片离子是通过库仑爆炸过程产生的。NO^&lt;4+&gt;→N^&lt;2+&gt;+O^&lt;2+&gt;。

In order to clarify the role of light-dressed states in the dynamics of a multielectron molecule in intense laser fields, the dissociation processes, O_2^+→O^++O, in intense laser fields (100fs, 〜3×10^<14> W/cm^2) are studied at the laser wavelength of 795 nm and 398 nm on the basis of the momentum imaging maps of the O^+ fragment ions. The covariance map measurements are performed with high momentum resolution to assign securely the dissociation pathways. From the anisotropic momentum distribution of O^+ with respect to the laser polarization direction, the electronic states of O_2^+ are found to be coupled exclusively through parallel transitions in the course of the dissociation process. The released kinetic-energy of O^+ for both 795 nm and 398 nm are interpreted consistently by a sequential coupling model of light-dressed potential curves of O_2^+ in the quartet Π- state manifold.The dispersed fluorescence spectra of NO and O_2 were measured in the spectral range between 300 nm and 700 nm using a spectrometer equipped with a intensified CCD camera. The observed spectra exhibits a number of spectral lines, most of which were assigned to the electronic transition of the higher charged fragment ions, such as N^+, N^<2+>, O^+ and O^<2+>. A high-resolution (〜2 cm^<-1> ) measurement was performed for the N III 3^2P°→3^2S transition at 409.24 nm. The observed spectra show a doublet pattern when the laser polarization is directed towards the spectrometer, which is interpreted as a result of a large released kinetic energy imposed on the N^<2+> fragment ion through the Coulomb explosion of NO.Based on the kinetic energy estimated from the split pattern of the spectra, it was found that the N^<2+> fragment was produced through the Coulomb explosion process, NO^<4+>→N^<2+>+O^<2+>.