Molecular chemistry electron impact excitation

This relation (Landau Teller, 1936) demonstrates the adiabatic behavior of vibrational relaxation. Usually the Massey parameter at low gas temperatures is high for molecular vibration cox ox k which explains the adiabatic behavior and results in the exponentially slow vibrational energy transfer during the VT relaxation During the adiabatic collision, a molecule has enough time for mai vibrations and the oscillator can actually be considered stractureless, which explains such a low level of energy transfer. An exponentially slow adiabatic VT relaxation and intensive vibrational excitation by electron impact result in the unique role of vibrational excitation in plasma chemistry. Molectrlar vibrations for gases... 

Theoretical chemistry at York University was strengthened in the 1990s with the appointments of Bill Pietro in 1991 and Rene Fournier in 1996. Pietro wrote part of the Gaussian code as a graduate student and several modules of SPARTAN while an assistant professor at the University of Wisconsin. While he was in Madison he developed a research program based on molecular electronic devices.236 He expanded his interests to several facets of molecular electronics, including molecular electroluminescent materials, molecular electronic devices (diodes, switches, and sensors), and functionalized semiconductor nanoclusters.237 These new materials not only are scientifically very exciting, but they offer the possibility of revolutionary impact on the future of the electronics industry. 

The work summarized in this article relates to some of the most exciting areas of supramolecular chemistry. The interdependence of electron-transfer reactions with supramolecular interactions is at the core of the development of switchable molecular devices. Furthermore, research in areas of supramolecular electrochemistry may open the way for technological applications such as responsive (intelligent) materials. A possible impact in the field of electrochemical sensors is also readily visualized from the work described here. 

Three modem developments have been produced in the last years that are the key for the comprehension of the photophysics and photochemistry of many chemical and biochemical phenomena (1) rapid advances in quantum-chemical methods allow to study the excited states with high accuracy (2) improved molecular beams techniques permit studies of isolated molecules, despite their sometimes low vapor pressme and propensity for thermal decomposition, and (3) the revolutionary impact that femtosecond laser and multiphoton techniques have had on the study of the electronic energy relaxation processes. Indeed, now it is possible to get information about reaction intermediates at very short times from femtochemical techniques, and, more than ever, the participation of quantum chemistry to interpret such findings has become crucial. A constructive interplay between theory and experiment can provide an insight into the chemistry of the electronic state that cannot be easily derived from the observed spectra alone. 

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