WHY SPIN EQUALS 1, 2 SPECIES HAVE NO ELECTRON-PARAMAGNETIC-RESONANCE SIGNAL UNDER NORMAL CONDITIONS - POSSIBLE DETECTION BY ELECTRON-PARAMAGNETIC-RESONANCE AT FREQUENCY CLOSE TO D-VALUE

A universal EPR simulation program has been created by the author, whi ch is based on the following spin Hamiltonian equation: H = g beta B.S + D{S-z(2) - S(S + 1)/3} + E(S-x(2) - S-y(2)) where D and E are the a xial and rhombic zero-field splitting parameters, respectively. The pr ogram can be used for simulation of EPR spectra with half-integer elec tronic spin (S = n/2, n = 3, 5, 7, 9) systems. In this article, the in teger spin (S = n/2, n = 2, 4) systems are also considered. The EPR si mulation results show that when D > frequency, no EPR signal can be se en from EPR simulation; when D approximate to frequency, whichever X/Q /W-band is used, the EPR signal can be seen on the basis of the simula ted EPR results presented. (C) 1996 Elsevier Science Inc.