Adiabatic energy difference, nonadiabatic

The following column contains the leading nonadiabatic correction zer0, the zero-point energy defined in equation (14). The last column reports the adiabatic energy Eclass corrected by the zero-point term zero for n > 4 it leads to a different ordering of the spin states... 

Beyond this point, one must be aware of important differences between the two laws. The performance of work is directly linked to changes in energy of a system, so that the integrating factor q relevant to the First Law is unity. Furthermore, changes in S are tracked by the reversible transfer of heat across the boundaries of the system or by other reversible changes of state. Additional changes in S are incurred when irreversible processes occur this subject was treated in detail in Section 1.10. By contrast, alterations in E are tracked by performance of work, whether reversibly or irreversibly, under adiabatic conditions. Different changes in E are incurred when these processes take place under nonadiabatic conditions, as discussed in Section 1.7. 

Despite the fact that relaxation of rotational energy in nitrogen has already been experimentally studied for nearly 30 years, a reliable value of the cross-section is still not well established. Experiments on absorption of ultrasonic sound give different values in the interval 7.7-12.2 A2 [242], As we have seen already, data obtained in supersonic jets are smaller by a factor two but should be rather carefully compared with bulk data as the velocity distribution in a jet differs from the Maxwellian one. In the contrast, the NMR estimation of a3 = 30 A2 in [81] brought the authors to the conclusion that o E = 40 A in the frame of classical /-diffusion. As the latter is purely nonadiabatic it is natural that the authors of [237] obtained a somewhat lower value by taking into account adiabaticity of collisions by non-zero parameter b in the fitting law. 

That effective hamiltonian according to formula 29, with neglect of W"(R), appears to be the most comprehensive and practical currently available for spectral reduction when one seeks to take into account all three principal extramechanical terms, namely radial functions for rotational and vibrational g factors and adiabatic corrections. The form of this effective hamiltonian differs slightly from that used by van Vleck [9], who failed to recognise a connection between the electronic contribution to the rotational g factor and rotational nonadiabatic terms [150,56]. There exists nevertheless a clear evolution from the advance in van Vleck s [9] elaboration of Dunham s [5] innovative derivation of vibration-rotational energies into the present effective hamiltonian in formula 29 through the work of Herman [60,66]. The notation g for two radial functions pertaining to extra-mechanical effects in formula 29 alludes to that connection between... 

The local permutational symmetry [Aa ] [AB ] is restricted such that the total permutational symmetry [A] is contained in T a 1 [V . When [Aa] [Ab] and [Aa ] [AB ] are not equal the corresponding separated molecule energies are different. Then for [Aa] [AB] / [Aa ] [AB ], the [Aa] [Ab] and [Aa ] [AB ] states are on different potential surfaces, and the process (5-9) is nonadiabatic. Thus the nonadiabatic reaction (5-9) might be expected to be most probably when the spin-free adiabatic potentials approach close to one another, since this is just the condition for the breakdown of the adiabatic approximation (see Sect. IV). 

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