eprintid: 36642
rev_number: 27
eprint_status: archive
userid: 9047
dir: disk0/00/03/66/42
datestamp: 2025-05-28 09:33:22
lastmod: 2025-06-13 07:28:36
status_changed: 2025-05-28 09:33:22
type: doctoralThesis
metadata_visibility: show
creators_name: Zhang, Weiyu
title: Time-Resolved Fragmentation of Methane in Strong Laser Fields
subjects: ddc-530
divisions: i-130001
divisions: i-851340
adv_faculty: af-13
cterms_swd: Moleküle
cterms_swd: Fragmentierung
cterms_swd: Photoionisation
abstract: The ionization and dissociation dynamics of methane (CH4) in strong laser fields are studied in a series of near-infrared (NIR) pump-probe experiments with a Reaction Microscope
(ReMi) [1].
Upon few-cycle strong NIR pump pulses, methane is ionized to different cationic states and undergoes the Jahn-Teller distortions, leading to multiple dissociation pathways. A
time-delayed NIR probe pulse then induces Coulomb explosion (CE), leading to the rapid dissociation of the molecule into two or three fragments. In CE, the initial internuclear
distances can be determined by measuring the final kinetic energy release (KER). Combined with the angular distribution of the fragments, four distinct fragmentation processes are
identified and analyzed. Through the time-resolved study of methane photofragmentation, ‘molecular movies’ are reconstructed, enabling the investigation of the ultrafast molecular rearrangement dynamics.
In two-body fragmentation, atomic hydrogen dissociates from methane as either neutral hydrogen (H^0) or a proton (H^+), each exhibiting distinct angular emission characteristics.
Comparing features observed in atomic and molecular hydrogen dissociation provides insight into molecular structural dynamics.
Moreover, while molecular hydrogen is observed as a product in two-body fragmentation, it can also act as an intermediate species, contributing to the three-body dissociation channel (CH_4 → CH_2^+ + H^+ + H^+). Finally, the unexpected detection of H_3^+ raises fundamental
questions regarding its formation mechanism under strong-field conditions, suggesting new directions for future research.
date: 2025
id_scheme: DOI
id_number: 10.11588/heidok.00036642
ppn_swb: 1927541549
own_urn: urn:nbn:de:bsz:16-heidok-366429
date_accepted: 2025-04-30
advisor: HASH(0x559de7603e48)
language: eng
bibsort: ZHANGWEIYUTIMERESOLV20250526
full_text_status: public
place_of_pub: Heidelberg
citation:   Zhang, Weiyu  (2025) Time-Resolved Fragmentation of Methane in Strong Laser Fields.  [Dissertation]     
document_url: https://archiv.ub.uni-heidelberg.de/volltextserver/36642/1/Time_Resolved_Fragmentation_of_Methane_in_Strong_Laser_Fields__WeiyuZhang.pdf