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Contribution to theory of low-energy electron-molecule collisions
Dvořák, Jan ; Čížek, Martin (advisor) ; Čársky, Petr (referee) ; McCurdy, Clyde William (referee)
Collisions of low-energy electrons with molecules lead to excitation of vibrational degrees of freedom or even to bond dissociation. Such phenomena are not fully understood in the case of polyatomic targets since the theoretical treatment is complicated by the multidimensionality of the vibrational dynamics and the interaction of multiple short- lived electronic states. In this thesis, we extend the nonlocal theory of these processes by considering the vibronic coupling through the electron continuum. In particular, we study vibrational excitation of carbon dioxide and dissociation of the N-H bond of pyrrole. For carbon dioxide, the dynamics includes all vibrational modes and three electronic states. The model explains the long-time puzzling shape of the observed energy-loss spectra as well as the origin of a fine structure revealed in a recent experiment. In the case of pyrrole, we study the effect of the motion of distant parts of the molecule on the dissociation. 1
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Excitation of molecules by cold electrons
Šulc, Miroslav ; Horáček, Jiří (advisor) ; Čárský, Petr (referee) ; Čížek, Martin (referee)
Title: Excitation of molecules by cold electrons Author: Miroslav Šulc Department / Institute: Institute of Theoretical Physics, Charles University in Prague Supervisor of the doctoral thesis: prof. RNDr. Jiří Horáček, DrSc., Institute of Theoretical Physics, Charles University Abstract: Several methods for low energy collisional processes are investigated. In the first part, attention is especially devoted to examination of applicability of the R-matrix method combined with the Schwinger-Lanczos (SL) variational principle for potential scattering with long-range forces. Next sections deal with the development of the interaction correlation-polarization (CP) potential in the framework of the Dis- crete Momentum Representation (DMR) method on the grounds of the Local Density Approximation in the Density Functional Theory (DFT) context. Obtained results are then utilized in body-frame (BF), static exchange + polarization (SEP), calcula- tions within an analysis of experimental data for e−-N2 scattering comprising a part of a larger project addressing theoretical examination of rotational excitations of small molecules in the gas phase induced by electron impact. For N2, a new phenomenon consisting in suppression of backward cross-section below 95 meV is observed and con- sequently attributed to...
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Excitation of molecules by cold electrons
Šulc, Miroslav ; Horáček, Jiří (advisor) ; Čárský, Petr (referee) ; Čížek, Martin (referee)
Title: Excitation of molecules by cold electrons Author: Miroslav Šulc Department / Institute: Institute of Theoretical Physics, Charles University in Prague Supervisor of the doctoral thesis: prof. RNDr. Jiří Horáček, DrSc., Institute of Theoretical Physics, Charles University Abstract: Several methods for low energy collisional processes are investigated. In the first part, attention is especially devoted to examination of applicability of the R-matrix method combined with the Schwinger-Lanczos (SL) variational principle for potential scattering with long-range forces. Next sections deal with the development of the interaction correlation-polarization (CP) potential in the framework of the Dis- crete Momentum Representation (DMR) method on the grounds of the Local Density Approximation in the Density Functional Theory (DFT) context. Obtained results are then utilized in body-frame (BF), static exchange + polarization (SEP), calcula- tions within an analysis of experimental data for e−-N2 scattering comprising a part of a larger project addressing theoretical examination of rotational excitations of small molecules in the gas phase induced by electron impact. For N2, a new phenomenon consisting in suppression of backward cross-section below 95 meV is observed and con- sequently attributed to...
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