Metastable states of negative ions often drive their nuclear motion via vibrational excitation or dissociative electron attachment (DEA) channels. During the last two decades these states, called resonances, were found to be responsible for processes with a wide variety of applications in medicine, biology, nanotechnology and astrochemistry. In the presented work we will report on a computational method, Discrete Momentum Representation (DMR) for calculations of vibrationally inelastic spectra of polyatomic molecules. The interaction model is based on the first principles, however, the correlation-polarization effects are accounted for by the density functional theory (DFT). Resonant cross sections are examined for several polyatomic hydrocarbon molecules. In the previous studies [1,2] the observed electron intensities for vibrational excitation of benzene served as a guide to lay foundations for resonant symmetry selection rules of vibrational excitations by electron impact. Their findings are based on examination of the following matrix element 〈χ1| [Γ2] |χ0〉 where is the symmetry of the resonance and are the initial and final vibrational states, respectively. Our detailed theoretical and experimental study of cyclopropane [3] and diacetylene [4] has revealed that the resonant wave function may leak through different symmetry in lower partial waves (p-wave) while still causing strong vibrational excitation of modes that are exempt from the above rule. An example of such exception in shown in figure 1. References S.F. Wong and G.J. Schulz Phys. Rev. Lett. 35 (1975) 1429 G.A. Gallup J. Chem. Phys. 99 (1993) 827 R. Čurík, P. Čársky, and M. Allan Phys. Rev. A 86 (2012) 062709 R. Čurík, I. Paidarová, M. Allan, and P.Čársky J. Phys. Chem. A 118 (2014) 9734

Role of resonances in vibrational excitation of polyatomic molecules

251st National Meeting (2016)

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