NUCLEAR QUADRUPOLE RESONANCE SPECTRUM OF B11 IN KERNITE

Abstract

The pure quadrupole resonance frequencies of B11 nuclei at two different sites (denoted by E and F) in a single crystal of kernite (Na2B4O7.4H2O) have been determined both by observing the B11 resonances in zero external magnetic field, and also by investigating their Zeeman splitting in magnetic fields up to 30 gauss. The values obtained are 1281.1 ± 2 and 1287.0 ± 1 kc./sec. for the E and F sites respectively. These frequencies agree within experimental error with the values 1286 ± 4 and 1287 ± 3 kc./sec. predicted on the basis of studies in a magnetic field of 7000 gauss. The agreement for the F site is much better than for the E site. These zero field resonances have also been observed in a polycrystalline sample. The observed weak field Zeeman splitting for the single crystal agrees very well with that calculated from high field data for F sites, but at present disagrees with the corresponding calculation for E sites. A Na23 pure quadrupole resonance in kernite has also been measured at 1560.0 ± 1 kc./sec. The second Na23 resonance expected from high field work has not been observed to date.