HYPERFINE SUBLEVEL CORRELATION SPECTROSCOPY IN LITHIUM SILICATE-GLASSES

The structure of gamma-irradiated (Li2O)(0.1)(SiO2)(0.9) glass has bee n studied with two-dimensional hyperfine sublevel correlation spectros copy (HYSCORE). The theoretical evaluation of the HYSCORE experimental data revealed the existence of weak couplings between the electron sp in and nearby ii. The anisotropic hyperfine coupling T is equal to 4.0 MHz suggesting a nonbridging oxygen-Li distance of 2.0 Angstrom and a n angle of +/-60 degrees away from the g(z) axis. The A(iso) value is equal to 0.5 MHz, corresponding to 0.135% contribution of the ii 2s or bital to the ground state. Thus, an estimation can be made of the cova lent character of the bond between the nonbridging oxygen and the alka li. (C) 1998 American Institute of Physics. [S0021-9606(98)51343-8].