Time-resolved photoelectron spectroscopy nonadiabatic dynamics

Hudock et al. [126] used the ab initio molecular dynamics multiple spawning method to go beyond the static picture based on PES and include the time dependent dynamical behavior and predict time-resolved photoelectron spectroscopy results. According to these results the first ultrafast component of the photoelectron spectra of uracil corresponds to relaxation on the S2 minimum rather than nonadiabatic transitions to the Si state. The authors suggest that the radiationless relaxation from... 

TIME-RESOLVED PHOTOELECTRON SPECTROSCOPY OF NONADIABATIC DYNAMICS IN POLYATOMIC MOLECULES... 

Photoionization out of several neutral states to several cation states may be simply included as separate terms of a split-operator scheme, assuming the ionized states do not strongly couple. Alternately, when the different ionization channels interact weakly, ionization out of each channel may be computed separately and the results combined. Examples of nonadiabatic dynamics seen through time-resolved photoelectron spectroscopy will be seen in Secs. 5.2 and 5.4. In the rest of this section, we will see examples of the diabatic representation for two classes of nonadiabatic interaction, the avoided crossing (Sec. 5.2.1.1) and the conical intersection (Sec. 5.2.1.2), and then discuss the necessary extensions to the standard vibrational wavefunction time-propagating schemes. 

In Chapter 5, we have studied some of the effects of laser fields on chemical dynamics. In particular, we have investigated how time-resolved photoelectron spectroscopy can be used as a very good means to monitor the femtosecond-scale nuclear dynamics such as the passage across nonadia-batic regions. The modulation of nonadiabatic interactions (both avoided crossing and conical intersection) is also among the main subjects from the view point of control of chemical reaction. Chapter 7, on the other hand, has treated nonadiabatic electron wavepacket dynamics relevant to chemical reactions. Here in this chapter, we therefore rise to the theory of electron dynamics in laser fields mainly associated with chemical dynamics. 

Electron dynamics of photoionization states in the course of nonadiabatic transition is one of the important molecular processes. It can be applied to the studies on the following dynamical processes Tracking the history of electronic and vibrational states wandering among the excited states in laser fields with designed optical pulses. These time-dependent transient states should be able to be monitored in terms of time-resolved photoelectron spectroscopy [14, 353]. Inner shell ionization from a deep core level and the concomitant electronic state avalanches (decay) towards the hole, which may be accompanied by autoionization, is also quite interesting. In a... 

In summary, time-resolved photoelectron imaging spectroscopy with the very high time-resolution of 22 fs using two-colour deep UV pulses and ab initio nonadiabatic dynamics simulations have for the first time revealed the ultrafast deactivation processes from S2 to So state in furan. Joint theoretical and experimental results represent a general approach for investigation of ultrafast photochemical reactions, allowing to identify the fingerprints of the character of electronic states with an unprecedented precision. 

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