Investigation of Self-and Foreign Gas Collision-induced Transitions between M-resolved Rotational Levels of OCS

1982 ◽  
Vol 37 (4) ◽  
pp. 358-370 ◽  
Author(s):  
H. Mäder
Keyword(s):  
Energy Levels ◽  
Double Resonance ◽  
Rotational Energy ◽  
Level System ◽  
First Order

Abstract Four-level MW-MW double resonance experiments on rotational Stark levels j = 0, 1, 2 and 3 of OCS have been performed to investigate transfer of rotational energy by collisions of OCS with OCS, He, Ne, Ar, Kr, H2, N2, O2, and CH3F. Theoretical arguments are given for the interpretation of the experimentally determined η-values by considering Bloch-type equations of an "embedded" four-level system with ±M degeneracy of the energy levels. The results indicate significant deviations from first order dipole collisional interaction.

On the Analysis of Steady State Microwave Double Resonance Experiments: Level Degeneracies and M Dependence

1975 ◽  
Vol 53 (23) ◽  
pp. 2593-2605 ◽  
Author(s):  
R. M. Lees
Keyword(s):  
Steady State ◽  
Rate Constants ◽  
Double Resonance ◽  
Rotational Energy ◽  
Level System ◽  
First Order ◽  
Absolute Agreement ◽  
Transfer Signal ◽  
Collisional Rate ◽  
Dipolar Model

The analysis of data on collisional transfer of rotational energy obtained by the technique of steady state four-level microwave double resonance is reviewed, with emphasis on the roles of the spatial degeneracies of the levels and the M dependence of their populations. Exact expressions are given for the collisional transfer signal in a general four-level system, with the level degeneracies included rigorously, and with M dependent and M independent contributions formally separated. The possible effects of the M dependence are illustrated for several test systems of CH3OH, with the use of a simplified first-order dipolar model for the collisional rate constants. Collisional transfer signals calculated with this model for a number of CH3OH systems are in reasonable relative agreement with observed values, but in poor absolute agreement. It is suggested that the latter feature may be due to neglect of higher-order transitions in the simple dipolar model.

Quantization of coupled orbits in metals

1962 ◽  
Vol 270 (1340) ◽  
pp. 1-13 ◽  
Keyword(s):  
Magnetic Field ◽  
Perturbation Theory ◽  
Fourier Analysis ◽  
Level Density ◽  
Energy Levels ◽  
Interference Effects ◽  
Level System ◽  
First Order ◽  
Simple Network ◽  
First Order Perturbation

The failure of semi-elassical quantization of electron orbits in metals in the presence of a strong enough magnetic field (magnetic breakthrough) is discussed in an elementary fashion by means of first-order perturbation theory. The interference effects, which arise when orbits about different centres are coupled, are reproduced in a simple network analogue. Exact analysis of the network shows how the energy levels are broadened by the coupling and eventually reform into a different set of levels. Fourier analysis of the level density reveals what might be observed in the de Haas—van Alphen effect when magnetic breakthrough is significant, and it is concluded that in principle the whole evolution of the level system should be observable.

scholarly journals Hyperfine Structure and Relaxation Times of 4-Oxo-TEMPO/Methyl Alcohol Solutions in Weak and Strong Fields

1991 ◽  
Vol 46 (11) ◽  
pp. 976-982 ◽  
Author(s):  
M. Sünnetçioğlu ◽  
G. Bingöl ◽  
R. Sungur
Keyword(s):  
Free Radical ◽  
Hyperfine Structure ◽  
Transition Probabilities ◽  
Energy Levels ◽  
Double Resonance ◽  
Relaxation Times ◽  
Electronic Relaxation ◽  
First Order ◽  
Saturation Method ◽  
First Order Perturbation

AbstractThe hyperfine structure of the 4-Oxo-TEMPO (2,2,6,6-tetramethyl-4-oxopiperidin-oxyl-l) free radical was investigated. Theoretical investigation includes four methyl groups protons close to the unpaired electron. Energy levels and transition probabilities were found by using second order and first order perturbation theory, respectively, and from these data theoretical spectra of the free radical were obtained. Diluted solutions in CH3-OH were prepared and the spectra were recorded with a double resonance spectrometer (1.53 mT) and Varian E-9X-band ESR spectrometer (~0.3 T). In order to understand the influence of time dependent phenomena on the linewidths, electronic relaxation times of 4-Oxo-TEMPO and its perdeuterated form (PDT) were measured at two different fields by using cw saturation method.

M-dependence of collisional transfer of rotational energy in methyl alcohol: the (4−1 ← 30)p – (40 ← 31)s system

1978 ◽  
Vol 56 (11) ◽  
pp. 1417-1421 ◽  
Author(s):  
R. M. Lees
Keyword(s):  
Energy Transfer ◽  
Matrix Element ◽  
Simple Model ◽  
Transition Rate ◽  
Double Resonance ◽  
Rotational Energy ◽  
Dipole Matrix Element ◽  
Level System ◽  
Rotational Energy Transfer ◽  
Good Agreement

An M-resolved microwave double resonance study of collision-induced rotational energy transfer has been carried out for the (4−1 ← 30)p – (40 ← 31)s four-level system of CH3OH. Spectra are reported for each distinct combination of pump and signal M-components. The observed M-dependence of the double resonance signals is in good agreement with a very simple model of the collisional transfer in which a transition rate constant is taken to depend only on the square of the dipole matrix element for the transition.

scholarly journals Intercombination Transitions between Levels X1Σg+ and A 3Πu in C2

1987 ◽  
Vol 120 ◽  
pp. 103-105
Author(s):  
J. Le Bourlot ◽  
E. Roueff
Keyword(s):  
Transition Probabilities ◽  
Energy Levels ◽  
Wave Functions ◽  
Spin Orbit Coupling ◽  
Energy Matrix ◽  
First Order ◽  
Emission Transition ◽  
Intercombination Transition ◽  
The One ◽  
Potential Curves

We present a new calculation of intercombination transition probabilities between levels X1Σg+ and a 3Πu of the C2 molecule. Starting from experimental energy levels, we calculate RKR potential curves using Leroy's Near Dissociation Expansion (NDE) method; these curves give us wave functions for all levels of interest. We then compute the energy matrix for the four lowest states of C2, taking into account Spin-Orbit coupling between a 3Πu and A 1Πu on the one hand and X 1Σ+g and b 3Σg− on the other. First order wave functions are then derived by diagonalization. Einstein emission transition probabilities of the Intercombination lines are finally obtained.

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