Large-amplitude

Modem photochemistry (IR, UV or VIS) is induced by coherent or incoherent radiative excitation processes [4, 5, 6 and 7]. The first step within a photochemical process is of course a preparation step within our conceptual framework, in which time-dependent states are generated that possibly show IVR. In an ideal scenario, energy from a laser would be deposited in a spatially localized, large amplitude vibrational motion of the reacting molecular system, which would then possibly lead to the cleavage of selected chemical bonds. This is basically the central idea behind the concepts for a mode selective chemistry , introduced in the late 1970s [127], and has continuously received much attention [10, 117. 122. 128. 129. 130. 131. 132. 133. 134... 

Technology developments are revolutionizing the spectroscopic capabilities at THz frequencies. While no one teclmique is ideal for all applications, both CW and pulsed spectrometers operating at or near the fiindamental limits imposed by quantum mechanics are now within reach. Compact, all-solid-state implementations will soon allow such spectrometers to move out of the laboratory and into a wealth of field and remote-sensing applications. From the study of the rotational motions of light molecules to the large-amplitude vibrations of... 

Smith T J and Cina J A 1996 Toward preresonant impulsive Raman preparation of large amplitude J. 

MMOs have been observed in many experiments. Typically, a MMO consists of one or more large amplitude oscillations followed by several small amplitude oscillations. The size of tire small oscillations may grow slowly. Suppose L large oscillations are followed by s small oscillations, where L and s are integers, tlien tliis MMO can be... 

Kinetic energy Small amplitude Large amplitude Exact... 

The approach developed by Jungen and Merer (JM) [24] is of a similar level of sophistication. The main difference is that IM prefer to remove the coupling between the electronic states by a transformation of the Hamiltonian matrix (i.e., vibronic energy matrix), rather that of the Hamiltonian itself. They first calculate the large amplitude bending functions for one of the adiabatic potentials, as if it belonged to a E electronic state. These functions are used as... 

Large amplitude (floppy) vibrational modes often exhibit significant anharmonicity that may increase errors in computed frequencies. In addition to anharmonicity, usually there is coupling between vibrational modes. 

If the viscous contribution were absent, the solution to this problem would be characterized by a resonance frequency close to which the application of small driving forces results in displacements of large amplitude. 

ANE Garcia. Large-amplitude nonlinear motions m proteins. Phys Rev Lett 68 2696-2699, 1992. 

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