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Title: Effects of the nanoplasma on the energetics of Coulomb explosion of molecular clusters in ultraintense laser fields

Abstract

We report on theoretical and computational studies of electron and nuclear energies in the Coulomb explosion of (D{sub 2}){sub n/2} clusters (n=250-33 000, cluster radius R{sub 0}=11 A-55 A) coupled to ultraintense Gaussian laser fields (laser peak intensities I{sub M}=10{sup 15}-10{sup 18} W cm{sup -2}, pulse widths {tau}=25-50 fs, and frequency {nu}=0.35 fs{sup -1}). Molecular dynamics simulations were fit by semiempirical relations for the average E{sub av} and maximal E{sub M} ion energies and for their dependence on the cluster radius (R{sub 0}) and on the laser parameters. This revealed two kinds of Coulomb explosion domains separated by the border radius R{sub 0}{sup (I)}, which marks complete cluster outer ionization and which depends on I{sub M} and {tau}, (i) the cluster vertical ionization (CVI) domain (R{sub 0}<R{sub 0}{sup (I)}), where E{sub av}, E{sub M}{proportional_to}R{sub 0}{sup 2} is independent of the laser parameters, (ii) the non-CVI domain (R{sub 0}>R{sub 0}{sup (I)}), which prevails at lower laser intensities over a broad region of cluster sizes (i.e., at I{sub M}=10{sup 15} W cm{sup -2}, R{sub 0}>R{sub 0}{sup (I)}=6.2 A for {tau}=25 fs, and R{sub 0}>R{sub 0}{sup (I)}=9.5 A for {tau}=50 fs). The effects of the persistent nanoplasma on Coulomb explosion in the non-CVImore » domain are manifested by a distinct cluster size dependence, i.e., E{sub av}{proportional_to}R{sub 0}{sup {eta}} ({eta}=0) and E{sub M}{proportional_to}R{sub 0}{sup {eta}} ({eta}=1) for R{sub 0}>(2.0-2.5)R{sub 0}{sup (I)}, and by a bimodal distribution of the ion kinetic energies. The energetics of Coulomb explosion in the non-CVI domain and its dependence (or independence) on the cluster size and laser parameters was semiquantitatively described by a cold nanoplasma model, which is based on a lychee configuration of the cluster charge, and which induces Coulomb explosion in the presence of the persistent nanoplasma. The results of our analyses are general for the cluster size dependence of the energetics of Coulomb explosion of multicharged elemental and molecular Xe{sub n}, (CH{sub 4}){sub n}, and (DI){sub n} clusters in the non-CVI domain.« less

Authors:
;  [1]
  1. School of Chemistry, Tel Aviv University, Ramat Aviv, 69978 Tel Aviv (Israel)
Publication Date:
OSTI Identifier:
20786726
Resource Type:
Journal Article
Journal Name:
Physical Review. A
Additional Journal Information:
Journal Volume: 73; Journal Issue: 1; Other Information: DOI: 10.1103/PhysRevA.73.013202; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1050-2947
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; COMPUTERIZED SIMULATION; COULOMB EXCITATION; DEUTERIUM; DISSOCIATION; DISTRIBUTION; ELECTRONS; IONS; LASER RADIATION; LASERS; METHANE; MOLECULAR CLUSTERS; MOLECULAR DYNAMICS METHOD; PHOTOIONIZATION; PHOTOLYSIS; PHOTON-MOLECULE COLLISIONS; PULSES

Citation Formats

Last, Isidore, and Jortner, Joshua. Effects of the nanoplasma on the energetics of Coulomb explosion of molecular clusters in ultraintense laser fields. United States: N. p., 2006. Web. doi:10.1103/PHYSREVA.73.0.
Last, Isidore, & Jortner, Joshua. Effects of the nanoplasma on the energetics of Coulomb explosion of molecular clusters in ultraintense laser fields. United States. https://doi.org/10.1103/PHYSREVA.73.0
Last, Isidore, and Jortner, Joshua. 2006. "Effects of the nanoplasma on the energetics of Coulomb explosion of molecular clusters in ultraintense laser fields". United States. https://doi.org/10.1103/PHYSREVA.73.0.
@article{osti_20786726,
title = {Effects of the nanoplasma on the energetics of Coulomb explosion of molecular clusters in ultraintense laser fields},
author = {Last, Isidore and Jortner, Joshua},
abstractNote = {We report on theoretical and computational studies of electron and nuclear energies in the Coulomb explosion of (D{sub 2}){sub n/2} clusters (n=250-33 000, cluster radius R{sub 0}=11 A-55 A) coupled to ultraintense Gaussian laser fields (laser peak intensities I{sub M}=10{sup 15}-10{sup 18} W cm{sup -2}, pulse widths {tau}=25-50 fs, and frequency {nu}=0.35 fs{sup -1}). Molecular dynamics simulations were fit by semiempirical relations for the average E{sub av} and maximal E{sub M} ion energies and for their dependence on the cluster radius (R{sub 0}) and on the laser parameters. This revealed two kinds of Coulomb explosion domains separated by the border radius R{sub 0}{sup (I)}, which marks complete cluster outer ionization and which depends on I{sub M} and {tau}, (i) the cluster vertical ionization (CVI) domain (R{sub 0}<R{sub 0}{sup (I)}), where E{sub av}, E{sub M}{proportional_to}R{sub 0}{sup 2} is independent of the laser parameters, (ii) the non-CVI domain (R{sub 0}>R{sub 0}{sup (I)}), which prevails at lower laser intensities over a broad region of cluster sizes (i.e., at I{sub M}=10{sup 15} W cm{sup -2}, R{sub 0}>R{sub 0}{sup (I)}=6.2 A for {tau}=25 fs, and R{sub 0}>R{sub 0}{sup (I)}=9.5 A for {tau}=50 fs). The effects of the persistent nanoplasma on Coulomb explosion in the non-CVI domain are manifested by a distinct cluster size dependence, i.e., E{sub av}{proportional_to}R{sub 0}{sup {eta}} ({eta}=0) and E{sub M}{proportional_to}R{sub 0}{sup {eta}} ({eta}=1) for R{sub 0}>(2.0-2.5)R{sub 0}{sup (I)}, and by a bimodal distribution of the ion kinetic energies. The energetics of Coulomb explosion in the non-CVI domain and its dependence (or independence) on the cluster size and laser parameters was semiquantitatively described by a cold nanoplasma model, which is based on a lychee configuration of the cluster charge, and which induces Coulomb explosion in the presence of the persistent nanoplasma. The results of our analyses are general for the cluster size dependence of the energetics of Coulomb explosion of multicharged elemental and molecular Xe{sub n}, (CH{sub 4}){sub n}, and (DI){sub n} clusters in the non-CVI domain.},
doi = {10.1103/PHYSREVA.73.0},
url = {https://www.osti.gov/biblio/20786726}, journal = {Physical Review. A},
issn = {1050-2947},
number = 1,
volume = 73,
place = {United States},
year = {Sun Jan 15 00:00:00 EST 2006},
month = {Sun Jan 15 00:00:00 EST 2006}
}