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Title: A search for the sulphur hexafluoride cation with intense, few cycle laser pulses

It is well established that upon ionization of sulphur hexafluoride, the SF{sub 6}{sup +} ion is never observed in mass spectra. Recent work with ultrashort intense laser pulses has offered indications that when strong optical field are used, the resulting “bond hardening” can induce changes in the potential energy surfaces of molecular cations such that molecular ions that are normally unstable may, indeed, become metastable enough to enable their detection by mass spectrometry. Do intense, ultrashort laser pulses permit formation of SF{sub 6}{sup +}? We have utilized intense pulses of 5 fs, 11 fs, and 22 fs to explore this possibility. Our results are negative: no evidence is discovered for SF{sub 6}{sup +}. However, multiply charged sulphur and fluorine ions from highly charged SF{sub 6}{sup q+} ions are observed that enable us to resolve the controversy regarding the kinetic energy release accompanying formation of F{sup +} fragment ions. Quantum chemical computations of field-distorted potential energy curves of SF{sub 6} and its molecular ion enable us to rationalize our non-observation of SF{sub 6}{sup +}. Our findings have implications for high harmonic generation from SF{sub 6} in the few-cycle regime.
Authors:
;  [1] ;  [2] ;  [1] ;  [3] ; ;  [4]
  1. Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400 005 (India)
  2. (India)
  3. Centre for Atomic and Molecular Physics, Manipal University, Manipal 576 104 (India)
  4. Indian Institute of Science Education and Research - Kolkata, Mohanpur 741 252 (India)
Publication Date:
OSTI Identifier:
22251427
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 139; Journal Issue: 19; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CALCULATION METHODS; CATIONS; FLUORINE IONS; HARMONIC GENERATION; KINETIC ENERGY; LASERS; MASS SPECTRA; MASS SPECTROSCOPY; MOLECULAR IONS; POTENTIAL ENERGY; PULSES; SULFUR; SULFUR FLUORIDES