High-resolution microwave spectroscopy of several weakly bound complexes.

Abstract

High resolution rotational spectra were obtained for a several weakly-bound complexes (WBC) and one transition metal organometallic molecule, cyclopentadienylnickel nitrosyl (CpNiNO), using pulsed-beam, Fourier transform microwave spectroscopy. The weakly-bound complexes included the two structural isomers of N₂O-HF, the planar bent asymmetric N₂O-HCN complex, the planar bent asymmetric N₂O-HCl complex, and the "stacked" H₂S-SO₂, and H₂S-CO₂ complexes. In all of the cases with the exclusion of the CpNiNO molecule, additional isotopic measurements were obtained to aid in the spectral and structural analyses of the weakly-bound complexes. Analysis of rotational spectra was used to determine several spectroscopic constants. For each WBC and CpNiNO rotational constants and some quartic distortion parameters were determined. In the experimental studies performed on N₂O-HCN and N₂O-HCl additional quadrupole coupling components were determined from the data analysis. Structural analyses were performed on all of the WBC's. Isotopic Kraitchman analysis was used as a comparative guideline in helping to select the lowest energy vibrationally-averaged structure. High resolution (0.005 cm⁻¹) infrared spectra for CpNiNO were obtained with the Fourier transform spectrometer in the Kitt Peak McMath Solar Telescope. Absorption spectra were measured in the 1750-1880 cm⁻¹ and 2500-3700⁻¹ regions. A program written by Dr. Clive Jarman, a postdoc in Dr. Peter Bernath's laboratory, was used to perform Loomis-Wood analysis of 2 significant patterns in the 2500-3700 cm⁻¹ range. The series determined from the Loomis-Wood analysis are given in the dissertation.