scholarly journals Raman spectroscopy of infrared multiphoton excited molecules

1988 ◽  
Vol 8 (2-4) ◽  
pp. 97-122 ◽  
Author(s):  
Jyhpyng Wang ◽  
Kuei-Hsien Chen ◽  
Eric Mazur
Keyword(s):  
Raman Spectroscopy ◽  
Energy Distribution ◽  
Vibrational Energy ◽  
Excited Molecules ◽  
Integrated Intensities ◽  
Vibrational Energy Distribution

This paper presents an overview of data obtained on the intramolecular vibrational energy distribution in infrared multiphoton excited CF2HCl, CF2Cl2, SF6 and CH3CHF2. All but CF2HCl show collisionless changes in the intensity of the spontaneous Raman signals after excitation, indicating that the excitation alters the population in the Raman active modes. A comparison of the spectrally integrated intensities of the Raman signals yields information on the distribution of vibrational energy over the modes of the molecule. The results for CF2Cl2 show a nonthermal distribution of energy after the excitation.

Vibrational energy distribution in plate excited with random white noise

2021 ◽  
Vol 263 (6) ◽  
pp. 965-969
Author(s):  
Tyrode Victor ◽  
Nicolas Totaro ◽  
Laurent Maxit ◽  
Alain Le Bot
Keyword(s):  
Boundary Conditions ◽  
Energy Distribution ◽  
White Noise ◽  
Numerical Simulations ◽  
Ray Tracing ◽  
Energy Analysis ◽  
Vibrational Energy ◽  
Statistical Energy Analysis ◽  
Vibrational Energy Distribution ◽  
Tracing Method

In Statistical Energy Analysis (SEA) and more generally in all statistical theories of sound and vibration, the establishment of diffuse field in subsystems is one of the most important assumption. Diffuse field is a special state of vibration for which the vibrational energy is homogeneously and isotropically distributed. For subsystems excited with a random white noise, the vibration tends to become diffuse when the number of modes is large and the damping sufficiently light. However even under these conditions, the so-called coherent backscattering enhancement (CBE) observed for certain symmetric subsystems may impede diffusivity. In this study, CBE is observed numerically and experimentally for various geometries of subsystem. Also, it is shown that asymmetric boundary conditions leads to reduce or even vanish the CBE. Theoretical and numerical simulations with the ray tracing method are provided to support the discussion.

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