Molecule resonance excitation

Collision-induced dissociation mass spectrum of tire proton-bound dimer of isopropanol [(CH2)2CHOH]2H. The mJz 121 ions were first isolated in the trap, followed by resonant excitation of their trajectories to produce CID. Fragment ions include water loss mJz 103), loss of isopropanol mJz 61) and loss of 42 anui mJz 79). (b) Ion-molecule reactions in an ion trap. In this example the mJz 103 ion was first isolated and then resonantly excited in the trap. Endothennic reaction with water inside the trap produces the proton-bound cluster at mJz 121, while CID produces the fragment with mJz 61. 

See also the theoretical description of a micro reactor for optical photocatalytic dissociation of non-linear molecules in [140]. Here, a mathematical model for a novel type of micro reactor is given. Rotating non-linear molecules at excitation of valent vibrations are considered, having a magnetic moment. Resonance decay of molecules can be utilized with comparatively weak external energy sources only. 

Eggeling, C., Widengren, J., Brand, L., Schaffer, J., Felekyan, S. and Seidel, C. A. (2006). Analysis of photobleaching in single-molecule multicolor excitation and Forster resonance energy transfer measurements. J. Phys. Chem. A 110, 2979-95. 

The observations of complex dynamics associated with electron-stimulated desorption or desorption driven by resonant excitation to repulsive electronic states are not unexpected. Their similarity to the dynamics observed in the visible and near-infrared LID illustrate the need for a closer investigation of the physical relaxation mechanisms of low energy electron/hole pairs in metals. When the time frame for reaction has been compressed to that of the 10 s laser pulse, many thermal processes will not effectively compete with the effects of transient low energy electrons or nonthermal phonons. It is these relaxation channels which might both play an important role in the physical or chemical processes driven by laser irradiation of surfaces, and provide dramatic insight into subtle details of molecule-surface dynamics. 

The Resonance Raman Effect (RRE) ca be observed when a molecule is excited by light with a frequency which falls under an obsorption band of the molecule. Whereas an excitation of this type commonly produces fluorescence for the gas phase, the fluorescence is usually suppressed for solutions, pure liquids, and sohd state samples. The Pre-Resonance Raman Effect (PRRE) is observed if the exciting line comes close to, but is not overlapping with an absorption band. 

It is easy then to write down the oscillation condition for a dye laser. In its simplest form a dye laser consists of a cuvette of length L [cm], with dye solution of concentration m [cm-3], and of two parallel end windows carrying a reflective layer, each of reflectivity R, which form the laser resonator. With mi molecules/ cm3 excited to the first singlet state, the dye laser will start oscillating at a wavelength A if the overall gain is equal to or greater than one ... 

The excited antenna molecule passes energy to a neighboring hlorophyll molecule (resonance energy transfer), exciting it. 

There can be a difference between the dissociation of polyatomic molecules and delayed ionization in the nature of the initial excitation. In ZEKE spectroscopy the state that is optically accessed (typically via an intermediate resonantly excited state) is a high Rydberg state, that is a state where most of the available energy is electronic excitation. Such a state is typically directly coupled to the continuum and can promptly ionize, unlike the typical preparation process in a unimolecular dissociation where the state initially accessed does not have much of its energy already along the reaction coordinate. It is quite possible however to observe delayed ionization in molecules that have acquired their energy by other means so that the difference, while certainly important is not one of principle. 

Vibrational excitation. There are two processes leading to vibrational excitation of a molecule when it collides with an electron the direct excitation and the resonance excitation where the electron is captured by the molecule. The direct vibrational excitation occurs owing to the dependence of the potential of interaction between an electron and a molecule on the internuclear spacings in the molecule. The cross section of direct excitation varies smoothly and is on the order of 10 17-10 16 cm2. The corresponding interaction time is much smaller than the period of nuclear vibrations. For describing this sort of excitation it is sufficient to use the momentum or the adiabatic approximation.105... 

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