Rotational population

El0.1 Calculate the most highly populated rotational energy level in U(g) at... 

For N2 molecules in their ground electronic and vibrational states at 300 K, determine the most highly populated rotational level Jmax-... 

Control Cultivate in fall to reduce overwintering populations rotate crops. 

The value of J for the most highly populated rotational level at the temperature T is given by... 

Evaluated In a photoionization mass spectrometric study from the difference in the thresholds for PHJ from PH3 and PHJ from PHg [1 ]. This value is only 4 kJ/mol higher than the almost coincident values calculated with the 4th-order Moller-Plesset perturbation procedure [1, 8] and with the generalized valence bond model [9]. - From the electron impact ionization of PH3 and PHg. - From the fluorescence excitation of PH3 photolysis fragments. - From the appearance potential of PHJ in electron impact studies of PH3 and the ionization potential of PHg. - From the appearance potential of PH2 from PH3 (2.2,2.3 eV) and the electron affinity of the PH2 radical (1.25 eV, see p. 62) [5] for earlier results (D<326 kJ/mol), see [10]. - From the highest populated rotational-vibrational level of HF, which is produced in a hydrogen abstraction reaction of PH3 with F atoms in a flowing afterglow experiment [6] for earlier results, see [11]. - Literature value based on the upper limit D<326 kJ/mol. 

Although the formation of products in different states is often analysed almost completely, only very few experiments yield state to state photodissociation cross sections. Usually photodissociation experiments are done with a gas at room temperature, where many rotational states are populated in the parent molecule. In this case product formation originates from many different initially populated rotational states of the parent molecule. Even in experiments, in which jet cooling is used to prepare low rotational states, usually more than one state is populated, in particular, if nuclear spins are important, like in H2 or H2O. 

Spacing for rotational levels, gives a spread of populated rotational states, generally peaking, depending upon energy spacing, around J 5-50. 

The temperature determines the population of the rotational energy levels. Rotational levels are close enough in energy that thermal energy is sufficient to cause some of the molecules to be in excited rotational states. Therefore, there is an increased probability of a transition from those excited rotational states to the level next highest in /. At some value of /, however, the ability of the temperature to thermally populate rotational levels decreases. A statistical treatment of the energy levels indicates that the approximate maximum-populated / quantum number, is... 

Determine the most populated rotational level, Imaxi fof 3 Sample of LiH (see problem above) at (a) 298 K,... 

At room temperature, the most highly populated rotational level of HF corresponds to / = 2. Neglect the corrections to the energy levels and use the harmonic-oscillator, rigid-rotor approximation. 

Various Physical Properties.—Radical cations of 2,5-dialkylthiothiophens have been obtained and their e.s.r. spectra interpreted in terms of unequally populated rotational isomers. The mass spectra of some simple thiophens and some azines derived from 2-acetyl- and 2-formyl-thiophens have been obtained. Molecular ion isomerizations occurring in 3-phenylthiophen and two brominated derivatives have been followed in both slow and fast reactions using C-labelling. Affinities, standard heats, and standard entropies of dyeing of some thiophen-containing azo dyes have been... 

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