Angular momentum spin-rotation coupling

The fine structure in purely rotational, rotational-vibrational, and electronic spectra of NH (ND) arises from the interaction of the unpaired electron spin with the orbital angular momentum (spin-orbit coupling constant A for the 11 states), from the interaction of the unpaired electron spins with each other and with the rotational angular momentum (spin-... 

The simplest example of angular momentum coupling is provided by the scaled spin-rotation coupling Hamiltonian... 

Yi and Ys - gyromagnetic ratio of spin 1 and spin S nuclear spin, rJS = intemuclear distance, tr= rotational correlation time, x< = reorientation correlation time, xj = angular momentum correlation time, Cs = concentration of spin S, Cq = e2qzzQ/h = quadrupole coupling constant, qzz = the electric field gradient, Q = nuclear electric quadrupole moment in 10 24 cm2, Ceff = effective spin-rotational coupling constant, a = closest distance of appropriate of spin 1 and spin S, D = (DA+DB)/2 = mutual translational self diffusion coefficient of the molecules containing I and S, Ij = moment of inertia of the molecule, Ao = a// - ol-... 

Where, C is the spin-rotation coupling constant (SRCC) and J is the rotational angular moment. This interaction becomes a relaxation mechanism if (i) the rotational angular momentum is modulated due to intermolecular interactions (torques) or (ii) the spin-rotational coupling becomes modulated when the orientation of the molecule is modulated due to collisions with other molecules. 

Another effect is the modulation of the rotational angular momentum of the ion and the interaction of this momentum with the spin angular momentum by means of its spin-rotational coupling. This mechanism (43) may be used to explain the absence of hyperfine splitting from vanadyl prophyrin in solution, whereas it is observed in the glassy state where spin-rotational relaxation will not be present. 

In the last relation C is the spin rotation coupling constant 4 and I the moment of inertia of a linear molecule. Tj is the angular momentum correlation time. 

Application of the symmetry correlation scheme to reaction (12) is summarized in Table 4 where N is the Himd s coupling case (b) rotational quantum number for O2 and - 5 is the difference of the Hund s coupling case (a) quantum numbers of total angular momentum and electron spin (5 = 1/2) angular momentum, respectively. To consider the high-symmetry isotopomer system first, the results in Table 4 indicate that only odd / collisions - 5 = odd) with 2 can lead... 

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