Mi Yonghao, Camus Nicolas, Fechner Lutz, Laux Martin, Moshammer Robert, Pfeifer Thomas
Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany.
Phys Rev Lett. 2017 May 5;118(18):183201. doi: 10.1103/PhysRevLett.118.183201. Epub 2017 May 2.
Channel-selective electron emission from strong-field photoionization of H_{2} molecules is experimentally investigated by using ultrashort laser pulses and a reaction microscope. The electron momenta and energy spectra in coincidence with bound and dissociative ionization channels are compared. Surprisingly, we observed an enhancement of the photoelectron yield in the low-energy region for the bound ionization channel. By further investigation of asymmetrical electron emission using two-color laser pulses, this enhancement is understood as the population of the autoionizing states of H_{2} molecules in which vibrational energy is transferred to electronic energy. This general mechanism provides access to the vibrational-state distribution of molecular ions produced in a strong-field interaction.
通过使用超短激光脉冲和反应显微镜，对H₂分子强场光电离中的通道选择性电子发射进行了实验研究。比较了与束缚电离通道和解离电离通道相关的电子动量和能谱。令人惊讶的是，我们观察到束缚电离通道在低能区域的光电子产率有所增强。通过使用双色激光脉冲对不对称电子发射进行进一步研究，这种增强被理解为H₂分子自电离态的布居，其中振动能量转移到了电子能量。这一普遍机制为研究强场相互作用中产生的分子离子的振动态分布提供了途径。
