Theoretical calculation on isotope shifts of N I

The special mass shift coefficient, ΔKSMS, and field parameter factor, Ful of four multiples, 3〖s 〗^4 P→3〖p 〗^4 P^°, 3〖s 〗^4 P→3〖p 〗^4 D^°, 3〖s 〗^2 D→5〖p 〗^2 D^°, and 3〖s 〗^2 P→3〖p 〗^2 P^°, of 14N and 15N were studied using the multi-configuration Dirac–Hartree–Fock method and the relativistic configuration interaction approach. The normal mass shift, special mass shift, field shift, and isotope shift of N I were derived from the theoretical calculated ΔKSMS, ΔKSMS and Ful, and compared with the reported experimental measurements and theoretical results.