부산대학교 도서관

The ultraviolet absorption spectra of nitrous oxide and its {sup 15}N isotopes over the wavelength range 197 to 172 nm and between 150 and 500 K show a weak continuous absorption and a pattern of diffuse banding that became pronounced at higher temperatures. The temperature dependence of the absorption spectrum results from the activation of the n{sub 2}{double_prime} bending mode. Deconvolution of the data shows that absorption by molecules in the (010) vibrational mode results in a spectrum of vibrational bands superimposed on a continuum. A weaker and nearly continuous spectrum results from the ultraviolet absorption by molecules in the (000) vibrational mode. Analysis of the structuring indicates n{sub 2}{double_prime} = (490 {+-} 10) cm{sup -1}. No rotational structure can be observed. Measurement of the n{sub 2}{double_prime} isotope shift is used to identify the quantum number of the upper state vibrational levels. Normal coordinate analysis of the excited state is used to determine a self-consistent set of molecular parameters: bond angle (115{sup o}), the values of n{sub 1}{prime} and n{sub 3}{prime} (1372 and 1761 cm{sup -1}, respectively), and the force constants of the upper state. It is suggested that the transitions observed are {sup 1}S{sup -}({sup 1}A{sup -}) {l_arrow} X- {sup 1}{sup +} and {sup 1}D {l_arrow} {tilde X} {sup 1}S{sup +}.