Positions and intensities in the 2 nu(4)/nu(1)/nu(3) vibrational system of(NH3)-N-14 near 3 mu m

Line positions and line intensities of the nu(1), nu(3), and 2 nu(4) bands of (NH3)-N-14 were analyzed using line positions from 0.0054 cm(-1) apodize d resolution FT spectra recorded at Orsay and using line intensities from 0 .011 cm(-1) unapodized resolution FT spectra recorded at Kitt Peak National Observatory. About 2110 lines with J' w less than or equal to 10 were assi gned from which 1832 line positions were fitted using an effective rotation -inversion Hamiltonian to achieve an rms of 0.085 cm(-1), Nearly 1000 line intensities were measured with an accuracy of 6% or better and modeled to 1 1 terms of dipole moment expansion to +/-9.4%. The bandstrengths of the nu( 1), nu(3), and 2 nu(4) bands (determined for the first time in the case of the 2 nu(4) band) are, respectively, 23.6(2), 11.8(1), and 2.82(4) cm(-2)/a tm at 296 K. A prediction of the line positions and intensities was generat ed for some similar to 2700 lines with intensities calculated greater than 1 x 10(-4) cm(-2) atm(-1) at 296 K, suitable for planetological purposes. T entative assignments involving 22 upper state levels of 4 nu(2)(s) were ide ntified, but these were not included in the modeling at the present stage. The theoretical model and the set of programs developed for treating the in frared system nu(1)/nu/2 nu(4) of ammonia are briefly discussed. (C) 1999 A cademic Press.