Chittra KedkaewPichet LimsuwanKanphot ThongchamSiwaporn MeejooKing Mongkuts University of Technology ThonburiMahidol University2018-07-122018-07-122008-10-20International Journal of Modern Physics B. Vol.22, No.25-26 (2008), 4740-4748021797922-s2.0-55949110545https://repository.li.mahidol.ac.th/handle/20.500.14594/19886The main purpose of this work is to present the ESR spectra and calculate the spin Hamiltonian parameters of14N and15N impurities in natural diamond. The ESR spectra of diamond crystal were measured on ESR spectrometer operating at X-band microwave frequency. The results of ESR spectra show that the diamond has a P1 center. This center gives rise to three strong resonance absorption peaks at θ = 90°, φ = 0° due to hyperfine interaction between electron spin and nuclear spin of14N. The ESR spectra of15N impurity consist of two satellites at the same rotation angle (φ). The effects of isolated substitution nitrogen on carbon atom produced a symmetric distortion from Tdto C3Vsymmetry. According to this symmetry, the resonance magnetic field positions of ESR spectra for the rotation angles of 0°, 90° and 180° are almost overlap. The g-factor values and spin Hamiltonian parameters of14N and15N are: g = 2.0019, A⊥= 29.73, A||= 40.24 and g = 2.0019, A⊥= -39.90, A||= -57.05, respectively. © 2008 World Scientific Publishing Company.Mahidol UniversityPhysics and AstronomyConference PaperSCOPUS