Curtin University Homepage
  • Library
  • Help
    • Admin

    espace - Curtin’s institutional repository

    JavaScript is disabled for your browser. Some features of this site may not work without it.
    View Item 
    • espace Home
    • espace
    • Curtin Research Publications
    • View Item
    • espace Home
    • espace
    • Curtin Research Publications
    • View Item

    Ab initio calculations of stationary points on the benzene-Ar and p-difluorobenzene-Ar potential energy surfaces: barriers to bound orbiting states

    Access Status
    Fulltext not available
    Authors
    Moulds, R.
    Buntine, Mark
    Lawrance, W.
    Date
    2004
    Type
    Journal Article
    
    Metadata
    Show full item record
    Citation
    Moulds, Rebecca J. and Buntine, Mark A. and Lawrance, Warren D. 2004. Ab initio calculations of stationary points on the benzene-Ar and p-difluorobenzene-Ar potential energy surfaces: Barriers to bound orbiting states. Journal of Chemical Physics 121 (10): pp. 4635-4641.
    Source Title
    Journal of Chemical Physics
    DOI
    10.1063/1.1772355
    ISSN
    00219606
    URI
    http://hdl.handle.net/20.500.11937/26042
    Collection
    • Curtin Research Publications
    Abstract

    The potential energy surfaces of the van der Waals complexes benzene–Ar and p-difluorobenzene–Ar have been investigated at the second-order Møller–Plesset (MP2) level of theory with the aug-cc-pVDZ basis set. Calculations were performed with unconstrained geometry optimization for all stationary points. This study has been performed to elucidate the nature of a conflict between experimental results from dispersed fluorescence and velocity map imaging (VMI). The inconsistency is that spectra for levels of p-difluorobenzene–Ar and –Kr below the dissociation thresholds determined by VMI show bands where free p-difluorobenzene emits, suggesting that dissociation is occurring. We proposed that the bands observed in the dispersed fluorescence spectra are due to emission from states in which the rare gas atom orbits the aromatic chromophore; these states are populated by intramolecular vibrational redistribution from the initially excited level [S. M. Bellm, R. J. Moulds, and W. D. Lawrance, J. Chem. Phys. 115, 10709 (2001)]. To test this proposition, stationary points have been located on both the benzene–Ar and p-difluorobenzene–Ar potential energy surfaces (PESs) to determine the barriers to this orbiting motion. Comparison with previous single point CCSD(T) calculations of the benzene–Ar PES has been used to determine the amount by which the barriers are overestimated at the MP2 level.As there is little difference in the comparable regions of the benzene–Ar and p-difluorobenzene–Ar PESs, the overestimation is expected to be similar for p-difluorobenzene–Ar. Allowing for this overestimation gives the barrier to movement of the Ar atom around the pDFB ring via the valley between the H atoms as ⩽204 cm−1 in S0 (including zero point energy). From the estimated change upon electronic excitation, the corresponding barrier in S1 is estimated to be ⩽225 cm−1. This barrier is less than the 240 cm−1 energy of30 2, the vibrational level for which the anomalous “free p-difluorobenzene” bands were observed in dispersed fluorescence from p-difluorobenzene–Ar, supporting our hypothesis for the origin of these bands.

    Related items

    Showing items related by title, author, creator and subject.

    • Rotational energy distributions of benzene liberated from aqueous liquid microjets: A comparison between evaporation and infrared desorption
      Maselli, O.; Gascooke, J.; Kobelt, S.; Metha, G.; Buntine, Mark (2006)
      We have measured the rotational energy distribution of benzene molecules both evaporated and desorbed by an IR laser from a liquid microjet. Analysis of the 6(0)(1) vibronic band of benzene has shown that the benzene ...
    • Implementation of Energy Saving Controller for Electromagnetic Ballast Fluorescent Lamps
      Cheong, Zhi Xiong; Barsoum, Nader (2010)
      Fluorescent lamps have proven to be the most efficient lighting device. However, energy losses have been found in electromagnetic ballast due to high harmonic distortion and low power factor so energy is consumed ...
    • Valence-band structure and critical point energies of diamond along [100]
      Edmonds, M.; Tadich, A.; Wanke, M.; O’Donnell, Kane; Smets, Y.; Rietwyk, K.; Riley, J.; Pakes, C.; Ley, L. (2013)
      Accurate valence-band dispersions E(k⊥) have been determined for the technologically relevant Γ-Δ-X symmetry direction of hydrogen-terminated diamond (100) using normal emission angle-resolved photoemission spectroscopy ...
    Advanced search

    Browse

    Communities & CollectionsIssue DateAuthorTitleSubjectDocument TypeThis CollectionIssue DateAuthorTitleSubjectDocument Type

    My Account

    Admin

    Statistics

    Most Popular ItemsStatistics by CountryMost Popular Authors

    Follow Curtin

    • 
    • 
    • 
    • 
    • 

    CRICOS Provider Code: 00301JABN: 99 143 842 569TEQSA: PRV12158

    Copyright | Disclaimer | Privacy statement | Accessibility

    Curtin would like to pay respect to the Aboriginal and Torres Strait Islander members of our community by acknowledging the traditional owners of the land on which the Perth campus is located, the Whadjuk people of the Nyungar Nation; and on our Kalgoorlie campus, the Wongutha people of the North-Eastern Goldfields.