H.-Y. Ni

Bio: H.-Y. Ni is an academic researcher from University of Science and Technology of China. The author has contributed to research in topics: Absorption spectroscopy & Fourier transform spectroscopy. The author has an hindex of 2, co-authored 2 publications receiving 38 citations.

Global modeling of the 14N216O line positions within the framework of the polyad model of effective Hamiltonian

Abstract: The global modeling of 14N216O line positions in the 0–9700 cm−1 region has been performed using the polyad model of effective Hamiltonian. The effective Hamiltonian parameters were fitted to the line positions collected from an exhaustive review of the literature. A number of lines perturbed by interpolyad resonance interactions were excluded from the fit. The dimensionless weighted standard deviation of the fit is 4.06. The fitted set of 138 effective Hamiltonian parameters allowed reproducing 37,353 measured line positions of 325 bands with an RMS value of 0.00423 cm−1.

High sensitivity CW-Cavity Ring Down Spectroscopy of N2O between 6950 and 7653 cm−1 (1.44–1.31 μm): II. Line intensities

Abstract: The room temperature absorption spectra of nitrous oxide, N2O, have been recorded in the 6950–7653 cm−1 spectral region at 2 and 10 Torr using a CW-CRDS spectrometer based on 24 fibered DFB lasers. The achieved sensitivity (noise equivalent absorption αmin≈5×10–11 cm−1) allowed detecting lines with intensities as low as 1×10–29 cm/molecule. In the preceding contribution (Lu Y, Mondelain D, Liu AW, Perevalov VI, Kassi S, Campargue A, J Quant Spectros and Radiat Transfer 2012;113:749–62), we reported the assignment of more than 7200 N2O lines in the region and the derivation of the corresponding spectroscopic parameters Gv, Bv, Dv and Hv. In the present work, more than 1300 14N216O absolute line intensities of cold and hot bands belonging to the ΔP=12, 13 and 14 series of transitions have been measured (P=2V1+V2+4V3 is the polyad number). The uncertainty of the obtained line intensity values varies from 4 to 7% for the majority of the lines. The obtained dataset extends importantly the set of measurements available in the literature, in particular for the ΔP =13 series for which previous data were very limited. The ΔP=12–14 effective dipole moment parameters were fitted to the intensity values measured in this work and available in the literature. The obtained sets of the dipole moment parameters allow reproducing the observed line intensities within their experimental uncertainties. The calculated intensities of the ΔP=12, 13 and 14 bands of 14N216O assigned by CRDS in the 6950–7653 cm−1 region are provided as supplementary material.

Global fittings of 14N15N16O and 15N14N16O vibrational–rotational line positions using the effective Hamiltonian approach

Abstract: An effective Hamiltonian built up to sixth order in the Amat–Nielsen ordering scheme describing all rovibrational energy levels in the ground electronic state and containing in explicit form all resonance interaction terms due to the approximate relations between harmonic frequencies ω1≈2ω2 and ω3≈4ω2 was applied to model the observed rovibrational line positions (collected from the literature) of 14N15N16O and 15N14N16O isotopologues of nitrous oxide. For 14N15N16O, 124 effective Hamiltonian parameters were fitted to near 28 000 observed line positions covering the 0.8–8860 cm−1 spectral range. The RMS of the weighted fit is 0.00126 cm−1 and dimensionless standard deviation is 1.48. For 15N14N16O, 121 effective Hamiltonian parameters were fitted to more than 31 000 observed line positions covering the same spectral interval. The RMS of the weighted fit is 0.00185 cm−1 and dimensionless standard deviation is 1.85. In both cases the models describe all available line positions with precision compatible to the measurement uncertainties. A number of local resonance perturbations was found and discussed. Among these perturbations there are interpolyad resonance Coriolis interactions. A comparison of HITRAN-2008 data with the calculations based on the fitted models is presented.