Ionic Pathways following UV Photoexcitation of the (HI)2 van der Waals Dimer
| ISSN: | 1089-5639 |
|---|---|
| Přístupová URL adresa: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::51864eb8b2dae0bb2e306318794d581b http://hdl.handle.net/2066/83367 |
| Rights: | RESTRICTED |
| Přírůstkové číslo: | edsair.doi.dedup.....51864eb8b2dae0bb2e306318794d581b |
| Autor: | Sergei A. Kochubei, David H. Parker, Georgii A. Bogdanchikov, Konstantin Vidma, Alexey V. Baklanov |
| Rok vydání: | 2010 |
| Předmět: |
Dimer
Photodissociation ComputingMethodologies_MISCELLANEOUS Ab initio Ionic bonding Photoexcitation ComputingMilieux_GENERAL chemistry.chemical_compound symbols.namesake chemistry Ab initio quantum chemistry methods Excited state symbols ComputingMethodologies_DOCUMENTANDTEXTPROCESSING Physical chemistry Molecular and Laser Physics Physical and Theoretical Chemistry Atomic physics van der Waals force |
| Zdroj: | The Journal of Physical Chemistry A, 114, 3067-3073 The Journal of Physical Chemistry A, 114, 9, pp. 3067-3073 |
| ISSN: | 1089-5639 |
| Popis: | Photodissociation of the (HI)(2) van der Waals dimers at 248 nm and nearby wavelengths has been studied using time-of-flight mass spectrometry and velocity map imaging. I(2)(+) product ions with a translational temperature of 130 K and "translationally hot" I(+) ions with an average kinetic energy of E(t) = 1.24 +/- 0.03 eV and angular anisotropy beta = 1.92 +/- 0.11 were detected as dimer-specific ionic photofragments. Velocity map images of the I(2)(+) and I(+) species were found to be qualitatively similar to those observed in the case of photoexcitation of the (CH(3)I)(2) dimer (J. Chem. Phys. 2005, 122, 204301). As in the case of the (CH(3)I)(2) dimer, the absence of neutral I(2)-specific features in the ionic species images from (HI)(2) allows us to eliminate neutral molecular I(2) as a precursor of I(+) and I(2)(+). Similar to the case of (CH(3)I)(2), we deduce that the observed I(2)(+) ions are produced in their (2)Pi(3/2,g) ground electronic state as a result of photodissociation of the ionized dimer (HI)(2)(+) + h nu --> I(2)(+) + .... The formation of "translationally hot" I(+) ions is attributed to photodissociation of nascent vibrationally excited I(2)(+) with an average vibrational energy of 1.05 +/- 0.10 eV. This vibrational excitation is explained by the nonequilibrium initial I-I distance in I(2)(+) arising in photodissociation of (HI)(2)(+) after prompt release of the light H atoms. On the basis of our ab initio calculated value for the I-I distance of (3.17 A) in the (HI)(2)(+) precursor dimer, the vibrational excitation of I(2)(+) is expected to be 1.02 eV, which is in quantitative agreement with our experimentally deduced value. The interpretation of our results was supported by ab initio calculations of the structure and energy of neutral and ionized dimers of HI at the MP4(SDTQ)//MP2 level. |
| Databáze: | OpenAIRE |
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