Infrared Absorption Spectroscopy Of ¹⁵N Substitutd Nitrous Oxide

High resolution ro-vibrational spectroscopy is an important tool to understand the the energy-level structures and energy transfer in the studies of polyatomic molecules. An observed spectral line yields the following information: frequency, intensity and line shape. It provides a window to get the information of the molecular structure, properties and interactions. It also plays an important role in photochemistry, astrophysical and environmental applications. The present thesis is devoted to the measurement and analysis of the excited vibrational states of the second most abundant isotopic species of nitrous oxide. The first chapter briefly reviews the main points of molecular spectroscopy; the second chapter presents structure and analysis of the ro-vibrational spectroscopy of linear molecules; the third chapter presents the spectroscopy studies of ¹⁴N¹⁵N¹⁶O and ¹⁵N¹⁴N¹⁶O.In the first chapter of the thesis,we give a simple introduction of the molecular spectroscopy, and the Hamiltonian model of the vibrations and rotations in a molecule.In the second chapter,we presents the introduction of the rotational and vibrational spectroscopy of linear molecules.The effective Hamiltonian method and how to fit the ro-vibrational spectra will be presentedThen we briefly introduce the theory of the energy levels and select rules of the linear molecule, three types of the transition of the linear molecule will be introduced.In the third chapter, we will concentrate on the infrared spectroscopy study of ¹⁴N¹⁵N¹⁶O and ¹⁵N¹⁴N¹⁶O. The absorption spectrum of the ¹⁴N¹⁵N¹⁶O and ¹⁵N¹⁴N¹⁶O enriched sample has been recorded with a Fourier-transform spectrometer in the spectral range 1250- 9000 cm-1. In this thesis, the investigated region is 1250-3500 cm-1. More than 9500 transitions of ¹⁴N¹⁵N¹⁶O and more than 13100 transitions of ¹⁵N¹⁴N¹⁶O were observed, and have been assigned based on the effective Hamiltonian model.We have also observed the spectra of ¹⁵N¹⁵N¹⁶O, ¹⁴N¹⁵N¹⁸O, ¹⁵N¹⁴N¹⁸O, ¹⁴N¹⁵N¹⁷O and ¹⁵N¹⁴N¹⁷O isotopologues. All together more than 28000 transitions are assigned due to 98, 101, 8, 3, 6, 1 and 1 bands for the ¹⁴N¹⁵N¹⁶O, ¹⁵N¹⁴N¹⁶O, ¹⁵N¹⁵N¹⁶O, ¹⁴N¹⁵N¹⁸O, ¹⁵N¹⁴N¹⁸O, ¹⁴N¹⁵N¹⁷O and¹⁵N¹⁴N¹⁷O. 108 of these 218 bands are newly reported, for 110 others of the rotational analysis is significantly extended and improved. For the bands which have been reported in literatures,we compared our work with Amiot's work and Toth's work. It is clear that our results has good agreement with that of Toth's work.