Depopulation

One should also notice that resonant excitation completely cycles the population between the lower and upper state with a period of 2ji/0. Non-resonant excitation also cycles population between the states but never completely depopulates the lower state. Finally, one should notice that non-resonant excitation cycles population between the two states at a faster rate than resonant excitation. 

A further advantage is the higher efficiency of the alexandrite laser because of its being a four-level laser. In the illustration in Figure 9.2(c), level 4 is a vibronic level and level 3 the zero-point level of the T2 state. Level 2 is a vibronic level of the 2 state and level 1 the zero-point level. Because of the excited nature of level 2 it is almost depopulated at room... 

Decay of the 1 and 2 lower levels of the laser transitions are rapid down to the 2 level this is depopulated mostly by collisions with helium atoms in the CO2 N2 Fie gas mixture which is used. 

Fluorescence excitation spectra of fairly large molecules in a supersonic jet are simplified, vibrationally, due to depopulation of low-lying vibrational levels in the ground electronic... 

The effect of temperature upon the situation in Fig. 5-5 is to modify the Boltzmann distribution. Lowering the temperature depopulates the higher-lying energy levels in favour of the lower. Therefore, susceptibility increases with decreasing temperature. Quantitative studies of the simple (first-order )... 

TPD studies tend to depopulate the molecular state sites during the Initial evacuation or carrier gas sweep. Thus, they are only sampling the slow sites which may well be dissociative as we have not examined this frequency region. The presence of an Intermediate molecular adsorbate would allow us to easily rationalize the possible change In observed molecularlty of the FRC results as the temperature was raised In that the dissociative sites would become accessible at the higher temperatures. 

Hence the steady-state population of triplets should increase under heavy-atom perturbation. However, this conclusion is valid only if unimolecular decay is the main route leading to triplet state depopulation. If bimolecular triplet quenching as shown below is more important than unimolecular decay by several orders of magnitude, kd could be increased as much or more than klte without decreasing the steady state triplet population<136) ... 

Since we have inhibited one pathway leading to triplet depopulation by deuteration, it is clear that it will take longer for the triplet to decay by the radiative pathway and the lifetime of the triplet is increased. If phosphorescence were the sole pathway leading to triplet decay, the measured triplet lifetime would correspond to the radiative lifetime and would be equal to... 

Surface Behavior. Most extraction processes deal with several phases. At the boundaries between these phases, an interface exists which can be populated with or depopulated of polymer. Situations in which the polymer should accumulate at the surface of one phase are 1. the flocculation of clays and fines or 2. the formation of foams, while situations in which the polymer should depopulate the surface of the phase boundary are 3 minimizing adsorption in mineral acid leaching or 4. minimizing surface tension with surfactants in oil recovery by miscible flooding.,... 

Herbich J, Kapturkiewicz A (1991) Radiative and radiationless depopulation of the excited intramolecular charge transfer states aryl derivatives of aromatic amines. Chem Phys 158 143-153... 

Both l3A"-4b and 23A"-4b are predicted to be minima on the potential surface at the CASSCF level.61 This is in contrast with the situation for 4a, where one triplet state is calculated to be a transition state for pseudorotation of the other.55-57 A derivative of triplet 4b has been implicated in solution trapping experiments,49 but there have been no reports of the direct observation of 4b. Facile intersystem crossing from the triplet ground state (13A") to the open-shell singlet state ( A"), followed by vibrational relaxation to one of the enantiomers of 3b (Fig. 12), would be expected to rapidly depopulate the 13A" state of 4b. Thus, direct detection of triplet 4b may prove to be much more difficult than detection of 4a was.lla... 

There is an urgent need to find feasible ways that would stop the ensuing depopulation in Ukraine, such ways to ensure survival that would work before die sustainable development concept has been implemented. In these times of a deep economic crisis, the economic and environment-related issues must be attacked simultaneously, in line with one strategy for a cleaner economy. This would be a change from a policy of anthropogenic impact assessment to that of at-source abatement of pollution. 

Energy-transfer experiments involving sensitisation and quenching allow us to selectively populate and depopulate excited states. This affords us a powerful tool whereby the particular excited state... 

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