ISSN:
1089-7690
Quelle:
AIP Digital Archive
Thema:
Physik
,
Chemie und Pharmazie
Notizen:
A new pump and probe technique for investigating vibrationally excited states via high resolution Raman spectroscopy is proposed. In a first step, a vibrational state, typically not accessible by a dipole moment transition from the ground state (IR forbidden, Raman allowed transition), is populated in a doubly pulsed stimulated Raman process. This state is long lived as the radiative decay to the ground state is highly inefficient. After a delay of several nanoseconds, the high resolution spectrum corresponding to a transition from this excited level is recorded. The second process follows the quasi-cw stimulated Raman spectroscopy scheme reported previously. Experimental aspects are discussed and the spectrum of 2ν1−ν1 of12CH4 is presented as an illustration of the technique. The analysis of this spectrum has been done in two ways: first, by fitting simultaneously the ν1 and 2ν1 bands using an isolated band model; second, using a model based on the tetradecad-pentad system. The standard deviations of both fits are of the order of the experimental precision. The interpretation of the spectroscopic constants of the corresponding models is discussed. © 1997 American Institute of Physics.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1063/1.475126
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