Systematic Investigation of the Reliability of the Frozen Nuclei Approximation for Short-Pulse Excitation: The Example of HCCI+

Abstract

In this work we quantitatively study the reliability of the frozen nuclei approximation for ultrafast dynamics. Specifically we study laser excitation of HCCI+ from its ground state to the first electronically excited state. The population of the first excited state is obtained by both the frozen nuclei approximation and by multidimensional nuclear dynamics. Detailed comparison of the results by the two methods are performed to provide quantitative criteria for the reliability of the frozen nuclei approximation for this system.

Probing Electronic Symmetry Reduction during Charge Migration via Time‐Resolved X‐Ray Diffraction

“…[37,74] On the other hand, Jia et al have discussed the importance of the nuclear dynamics during laser-induced charge migration in HCCI + . [75][76][77] It has been shown that the overlap of the vibrational wave packets associated with the different electronic states during the nuclear dynamics leads electronic decoherence and recoherence. [75,76] Thus, ignoring the role of nuclear motion for charge migration occurring on 60 fs is not a good approximation.…”

Ionization of HCCI Neutral and Cations by Strong Laser Fields Simulated With Time Dependent Configuration Interaction

“…The superposition between the X and A states of HCCI cation has been studied previously using high harmonic spectroscopy and advanced modeling. ( Kraus et al, 2015 ; Ding et al, 2017 ; Jenkins et al, 2018 ; Jia et al, 2019a ; Jia et al, 2019b ; Jia and Yang, 2022 ). However, due to the limited probing range of HHS, the wave packet motion beyond the first three femtoseconds has not been studied.…”

“…Recent theoretical investigations suggested the coherence will rapidly dephase after 5 fs and even rephase at a later time. ( Jia et al, 2019a ; Jia et al, 2019b ; Jia and Yang, 2022 ). Therefore, a new probing method with attosecond time resolution and a long probing range is needed.…”

“…Nuclear dynamics leads to dephasing which modulates the electron dynamics. ( Ding et al, 2017 ; Jenkins et al, 2018 ; Jia et al, 2019a ; Jia et al, 2019b ; Jia and Yang, 2022 ). This is addressed in a separate paper by Jia and Yang in this collection of articles on electronic and nuclear dynamics of molecules in intense laser fields.…”

“…This is addressed in a separate paper by Jia and Yang in this collection of articles on electronic and nuclear dynamics of molecules in intense laser fields. ( Jia and Yang, 2022 ). The focus of the present paper is on the use of strong field ionization to probe the electron dynamics of HCCI + .…”