The multi-photon dissociation of HCl(+) through three channels HCl(+)→H(1s|(2)S)+Cl(+)((3)P), H(+)+Cl((2)P(0)), and H((2)S)+Cl(+)((1)D) steered by intense femtosecond laser pulses are investigated theoretically using the quantum wave packet dynamics. The numerical calculations are performed in two cases without and with the coupling between the excited states. The results show that the dissociation is sensitive to the duration τ, peak intensity I(0), and the resonance of driving laser fields. In the case without the coupling, the effect of the permanent dipole moments on the dissociations dominates for τ < 15 fs, while with the increase of τ, the dissociation dynamics is mainly dominated by the transition dipole moment. In the case with the coupling, the above-threshold dissociation process is complex, and the non-resonant (λ = 400 nm) and resonant (λ = 800 and 1200 nm) laser fields lead to different variation of the branching ratios. The angle-resolved energy distribution is also discussed in detail.
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http://dx.doi.org/10.1063/1.4773022 | DOI Listing |
Sci Rep
January 2025
School of Physics and Information Technology, Shaanxi Normal University, Xi'an, 710062, Shaanxi, People's Republic of China.
Electron-nuclear coupling plays a crucial role in strong laser induced molecular dissociation dynamics. The interplay between electronic and nuclear degrees of freedom determines the pathways and outcomes of molecular fragmentation. However, a full quantum mechanical treatment of electron-nuclear dynamics is computationally intensive.
View Article and Find Full Text PDFPhys Chem Chem Phys
August 2024
Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, UK.
Infra-red multiple-photon dissociation spectroscopy on Xe-tagged Re/Si clusters, [ReSi], = 3-9, reveals intense absorption features around 400 cm, along with, in some cases, additional bands in the 250-350 cm window. A survey of the potential energy surface using density functional theory in conjunction with particle swarm optimisation indicates a growth pattern based on a growing network of Si atoms wrapped around the Re centre: the Si units can be viewed as fragments of a putative 16-vertex Frank-Kasper polyhedron. The structural evolution for the [ReSi] series differs significantly from the iso-electronic Mn series studied previously, where the metal ion is typically bound externally to the surface of a growing 3-dimensional Si cluster, the differences reflecting the greater accessibility of 5d 3d electron density.
View Article and Find Full Text PDFPhys Chem Chem Phys
April 2023
J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA.
The UV-induced photodissociation dynamics of iodomethane (CHI) in its A-band are investigated by time-resolved coincident ion momentum imaging using strong-field ionization as a probe. The delay-dependent kinetic energy distribution of the photofragments resulting from double ionization of the molecule maps the cleavage of the carbon-iodine bond and shows how the existence of a potential well in the di-cationic potential energy surfaces shapes the observed distribution at small pump-probe delays. Furthermore, the competition between single- and multi-photon excitation and ionization of the molecule is studied as a function of the intensity of the UV-pump laser pulse.
View Article and Find Full Text PDFAnal Chem
November 2022
Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K.
Ultraviolet photodissociation is a fast, photon-mediated fragmentation method that yields high sequence coverage and informative cleavages of biomolecules. In this work, 193 nm UVPD was coupled with a 12 Tesla FT-ICR mass spectrometer and 10.6 μm infrared multi-photon dissociation to provide gentle slow-heating of UV-irradiated ions.
View Article and Find Full Text PDFBio Protoc
April 2022
Department of Pharmacology and Physiology, University of Rochester, Rochester, NY, USA.
Changes in intracellular calcium drive exocrine cell activity. In the salivary gland, acetylcholine released from parasympathetic neurons mobilizes endoplasmic reticulum calcium stores in acinar cells, which consequently initiates saliva secretion. However, our understanding of the signaling cascade is mainly based on studies performed in enzymatically isolated cells.
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