Department of Electronic Engineering, Okayama University of Science
Abstract
Theoretical investigation of multiphoton processes in solids by rotary-saturation method in NMR is presented. In order to analize the results obtained by this method, it is necessary to introduce the conception of doubly rotating reference frame. The second quantization of a perturbing field, the calculation of the nth order time-dependent perturbation, dipole-dipole interaction and the motion of magnetization are all treated in this frame. Multiphoton transitions in solids have strong dependences on the time during perturbation, the strength of perturbing field and the angle between the direction of quantization and that of perturbing field. Rotary-saturation method produces easily magic angle at which the width of multiphoton absorption lines extremely narrow, so that even higher-order transitions can be observed separately each other
