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Title: Combined Vacuum Ultraviolet Laser and Synchrotron Pulsed Field Ionization Study of CH₂BrCl.

Abstract

The research described in this product was performed in part in the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. The pulsed field ionization-photoelectron (PFI-PE) spectrum of bromochloromethane (CH₂BrCl) in the region of 85 320–88 200 cm -1 has been measured using vacuum ultraviolet laser. The vibrational structure resolved in the PFI-PE spectrum was assigned based on ab initio quantum chemical calculations and Franck-Condon factor predictions. At energies 0–1400 cm ⁻1 above the adiabatic ionization energy (IE) of CH₂BrCl, the Br–C–Cl bending vibration progression (v₁⁺=0–8) of CH₂BrCl⁺ is well resolved and constitutes the major structure in the PFI-PE spectrum, whereas the spectrum at energies 1400–2600 cm -1 above the IE(CH₂BrCl) is found to exhibit complex vibrational features, suggesting perturbation by the low lying excited CH₂BrCl⁺(A²A") state. The assignment of the PFI-PE vibrational bands gives the IE(CH₂BrCl) =85 612.4±2.0 cm -1 (10.6146±0.0003 eV) and the bending frequencies v₁⁺(a₁')=209.7±2.0 cm -1 for CH₂BrCl⁺(X²A'). We have also examined the dissociative photoionization process, CH₂BrCl +hv→CH₂Cl ++Br +e -, in the energy range of 11.36–11.57 eV using the synchrotron based PFI-PE-photoion coincidence method, yielding themore » 0 K threshold or appearance energy AE(CH₂Cl⁺)=11.509±0.002 eV. Combining the 0 K AE(CH₂Cl⁺) and IE(CH₂BrCl) values obtained in this study, together with the known IE(CH₂Cl), we have determined the 0 K bond dissociation energies (D 0) for CH₂Cl+–Br (0.894±0.002 eV) and CH₂Cl–Br (2.76±0.01 eV). We have also performed CCSD(T, full)/complete basis set (CBS) calculations with high-level corrections for the predictions of the IE(CH₂BrCl), AE(CH₂Cl +), IE(CH₂Cl), D0(CH₂Cl +–Br), and D0(CH₂Cl–Br). The comparison between the theoretical predictions and experimental determinations indicates that the CCSD(T, full)/CBS calculations with high-level corrections are highly reliable with estimated error limits of <17 meV.« less

Authors:
 [1];  [1];  [1];  [2];  [3];  [3];  [3];  [3]
  1. Tsinghua Univ., Beijing (China)
  2. City Univ., Hong Kong (China)
  3. Univ. of California, Davis, CA (United States)
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
921388
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 126; Journal Issue: 18
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; BENDING; COINCIDENCE METHODS; DISSOCIATION; ENERGY RANGE; IONIZATION; LASERS; PHOTOIONIZATION; SYNCHROTRONS; VIBRATIONAL STATES; Environmental Molecular Sciences Laboratory

Citation Formats

Li, Juan, Yang, Jie, Mo, Yuxiang, Lau, Kai Chung, Qian, X M, Song, Y, Liu, Jianbo, and Ng, Cheuk-Yiu. Combined Vacuum Ultraviolet Laser and Synchrotron Pulsed Field Ionization Study of CH₂BrCl.. United States: N. p., 2007. Web. doi:10.1063/1.2730829.
Li, Juan, Yang, Jie, Mo, Yuxiang, Lau, Kai Chung, Qian, X M, Song, Y, Liu, Jianbo, & Ng, Cheuk-Yiu. Combined Vacuum Ultraviolet Laser and Synchrotron Pulsed Field Ionization Study of CH₂BrCl.. United States. doi:10.1063/1.2730829.
Li, Juan, Yang, Jie, Mo, Yuxiang, Lau, Kai Chung, Qian, X M, Song, Y, Liu, Jianbo, and Ng, Cheuk-Yiu. Fri . "Combined Vacuum Ultraviolet Laser and Synchrotron Pulsed Field Ionization Study of CH₂BrCl.". United States. doi:10.1063/1.2730829.
@article{osti_921388,
title = {Combined Vacuum Ultraviolet Laser and Synchrotron Pulsed Field Ionization Study of CH₂BrCl.},
author = {Li, Juan and Yang, Jie and Mo, Yuxiang and Lau, Kai Chung and Qian, X M and Song, Y and Liu, Jianbo and Ng, Cheuk-Yiu},
abstractNote = {The research described in this product was performed in part in the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. The pulsed field ionization-photoelectron (PFI-PE) spectrum of bromochloromethane (CH₂BrCl) in the region of 85 320–88 200 cm-1 has been measured using vacuum ultraviolet laser. The vibrational structure resolved in the PFI-PE spectrum was assigned based on ab initio quantum chemical calculations and Franck-Condon factor predictions. At energies 0–1400 cm⁻1 above the adiabatic ionization energy (IE) of CH₂BrCl, the Br–C–Cl bending vibration progression (v₁⁺=0–8) of CH₂BrCl⁺ is well resolved and constitutes the major structure in the PFI-PE spectrum, whereas the spectrum at energies 1400–2600 cm-1 above the IE(CH₂BrCl) is found to exhibit complex vibrational features, suggesting perturbation by the low lying excited CH₂BrCl⁺(A²A") state. The assignment of the PFI-PE vibrational bands gives the IE(CH₂BrCl) =85 612.4±2.0 cm-1 (10.6146±0.0003 eV) and the bending frequencies v₁⁺(a₁')=209.7±2.0 cm-1 for CH₂BrCl⁺(X²A'). We have also examined the dissociative photoionization process, CH₂BrCl+hv→CH₂Cl++Br+e-, in the energy range of 11.36–11.57 eV using the synchrotron based PFI-PE-photoion coincidence method, yielding the 0 K threshold or appearance energy AE(CH₂Cl⁺)=11.509±0.002 eV. Combining the 0 K AE(CH₂Cl⁺) and IE(CH₂BrCl) values obtained in this study, together with the known IE(CH₂Cl), we have determined the 0 K bond dissociation energies (D0) for CH₂Cl+–Br (0.894±0.002 eV) and CH₂Cl–Br (2.76±0.01 eV). We have also performed CCSD(T, full)/complete basis set (CBS) calculations with high-level corrections for the predictions of the IE(CH₂BrCl), AE(CH₂Cl+), IE(CH₂Cl), D0(CH₂Cl+–Br), and D0(CH₂Cl–Br). The comparison between the theoretical predictions and experimental determinations indicates that the CCSD(T, full)/CBS calculations with high-level corrections are highly reliable with estimated error limits of <17 meV.},
doi = {10.1063/1.2730829},
journal = {Journal of Chemical Physics},
number = 18,
volume = 126,
place = {United States},
year = {Fri May 11 00:00:00 EDT 2007},
month = {Fri May 11 00:00:00 EDT 2007}
}