کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5376790 | 1504330 | 2006 | 14 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Multistate and multimode vibronic dynamics: The Jahn-Teller and pseudo-Jahn-Teller effects in the ethane radical cation
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Multimode Jahn-Teller (JT) and pseudo-Jahn-Teller (PJT) coupling effects in the photoelectron spectrum of ethane are theoretically investigated. In this article, we focus on the vibronic structure of the second excited Bâ¼2Eu electronic manifold of the ethane radical cation which reveals an asymmetric band in the 14.5-16.5 eV ionization energy range in the experimental recordings. Ionization of an electron from the third occupied 1eu molecular orbital of ethane produces the radical cation in the degenerate Bâ¼2Eu electronic manifold, which is prone to the JT instability when distorted along the degenerate eg vibrational modes. The theoretical formalism employed here is based on a model diabatic Hamiltonian and a quadratic vibronic coupling scheme with the parameters derived from ab initio electronic structure calculations. The photoelectron band is calculated by carrying out quantum dynamical simulations in the coupled manifold of electronic states. The Bâ¼2Eu electronic manifold of the radical cation is estimated to be â¼2.75 eV and â¼2.40 eV above its Xâ¼2Eg and the Aâ¼2A1g electronic states, respectively. The symmetry selection rule suggests PJT coupling of these electronic states along the vibrational modes of eg/eu symmetry. The quadratic JT spectrum simulated within the Bâ¼2Eu electronic manifold shows two maxima at â¼Â 14.96 eV and â¼15.76 eV which are attributed to the two JT split adiabatic sheets of this electronic manifold. This is in good accord with their position observed at â¼15.0 eV and â¼15.8 eV, respectively, in the experimental recording. The diffuse structure of the overall band can be accounted to a large extent by considering the Aâ¼2A1g-Bâ¼2Eu PJT interactions. The overall shape of the theoretical band agrees very well with the experimental results. Further refinement of the theoretical results may be accomplished by including Xâ¼2Eg-Aâ¼2A1g-Bâ¼2Eu PJT interactions in the theoretical model. Importance of the latter vibronic interactions is also discussed in the text.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemical Physics - Volume 329, Issues 1â3, 26 October 2006, Pages 76-89
Journal: Chemical Physics - Volume 329, Issues 1â3, 26 October 2006, Pages 76-89
نویسندگان
R.R. Kumar, T.S. Venkatesan, S. Mahapatra,