New EPR spectra in diamonds with a high concentration of nitrogen atoms

Abstract

Abstract The EPR spectrum of a synthetic diamond, containing a high concentration of isolated substitutional nitrogen, N S (the P1 EPR centre), shows in addition to the spectrum of P1 three other features not previously observed in nitrogen containing diamond: 1. an ‘allowed’ pair spectrum close to that of P1 corresponding to interacting pairs of N S at three sites separated by 0.357–0.564 nm; 2. a ‘forbidden’ pair spectrum at about half of the magnetic field required for P1, with hyperfine structure characteristic of a pair of interacting nuclei with I =1, each with the same hyperfine parameters as P1: corresponding to a superposition of many pairs of separation greater than 0.7 nm; 3. a double quantum spectrum of P1, being an exact replica of the normal spectrum at twice the magnetic field.