Chirp Effect on CEP-Controlled Molecular Dissociation

Saba Arife Bozpolat*, Philipp Rosenberger, Marcelo F. Ciappina, Matthias F. Kling, I. Yavuz

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review


Intense, few-cycle laser fields enable a strong control over the electronic and nuclear dynamics of chemical reactions. Particularly, molecular dissociation in few-cycle chirp-free field has been well-understood (Yavuz et al., Phys Rev A 98:043413, 2018; Li et al., J Phys B 50:172001, 2017; Kling et al., Science 312(11262559):246–248, 2006). Going beyond this, in this study we theoretically studied the chirp effect of the intense laser pulse, as an additional controllable-parameter, on molecular dissociation using the numerical solutions of TDSE. We introduce the chirp to our equations with cos(ω0t + φ0 + ω0ηt22) term where ω0, φ0, η and τ are angular frequency, phase, chirp parameter and the FWHM duration, respectively The time variation of the laser pulse is shown for chirp-free and chirped cases. For a preliminary understanding we consider the two level model first. Then we solve the time-dependent Schrödinger (TDSE) equation for full investigation. The results for two-level model is presented in Fig. 35.1 (Bozpolat et al., Phys Rev A 100:06340, 2019). We consider various chirp values in our calculations, while maintaining the temporal bandwidth, and compare our results to the case with non-chirped laser pulse. We assume that H2+ are populated at the peak ionization times of H2, as found from CEP-included MO-ADK calculations. Reported dissociation probabilities are the weighted sums of these time-resolved dissociation probabilities and also vibrational wave-packets are FC-averaged. We observed that the chirp considerably modifies the dissociation and asymmetry. Dissociation asymmetry changes sign with chirp parameter (see Fig. 35.1 (d)). This is due to that the gerade and ungerade states mixes one more time before electron localization freezes out for positive chirp values. Therefore the localization and asymmetry occurs opposite nuclei for positive and negative chirp parameters.

Original languageEnglish
Title of host publicationNATO Science for Peace and Security Series B
Subtitle of host publicationPhysics and Biophysics
PublisherSpringer Science and Business Media B.V.
Number of pages2
StatePublished - 2022
Externally publishedYes

Publication series

NameNATO Science for Peace and Security Series B: Physics and Biophysics
ISSN (Print)1874-6500
ISSN (Electronic)1874-6535


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