Chittra KedkaewPichet LimsuwanKanphot ThongchamSiwaporn MeejooKing Mongkuts University of Technology ThonburiMahidol University2018-07-122018-07-122008-01-01Condensed Matter Theories. Vol.23, (2008), 452-4602-s2.0-84969677832https://repository.li.mahidol.ac.th/handle/20.500.14594/19102© 2009 by World Scientific Publishing Co. Pte. Ltd. All rights reserved. The main purpose of this work is to present the ESR spectra and calculate the spin Hamiltonian parameters of 14N and 15N 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= O°due to hyperne interaction between electron spin and nuclear spin of 14N. The ESR spectra of 15N impurity consist of two satellites at the same rotation angle. The eαects of isolated substitution nitrogen on carbon atom produced a symmetric distortion from Td to C3V symmetry. 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 of 14N and 15N are: g = 2:0019, A⊥= 29:73, A‖= 40:24 and g = 2:0019, A⊥= -39:90, A‖= -57:05, respectively.Mahidol UniversityChemistryEngineeringMaterials SciencePhysics and AstronomyChapterSCOPUS10.1142/9789812836625_0046