Perturbation allowed transitions in the infrared spectrum of ¹⁴ND₃: determination of the K-dependent parameters in the ground state

Abstract

Accurate values of the K-dependent constants (i) C, (i) D K and (i) H K in the ground state of 14 ND 3 , with i = s, a , have been determined for the first time thanks to the detections of 'perturbation allowed' transitions in the ν 1 , ν 2 , ν 3 , ν 4 , and 2ν 4 infrared bands. The rotation-inversion and inversion transitions from the literature, together with 7289 ground state combination differences from the infrared vibration-rotation-inversion transitions have been simultaneouslyanalysed. The adopted rotation-inversion Hamiltonian includes distortion constants up to the 8th power and the ∆k = ±3 and ∆k = ±6 interaction terms.Precise values of the diagonal constants and of the ∆k = ±3 interaction coefficients have been obtained. Accurate values of the ground state term values have been calculated for both s and a levels up to J = 21.