ULTRAVIOLET ABSORPTION SPECTRUM OF NITROUS OXIDE AS FUNCTION OF TEMPERATURE AND ISOTOPIC SUBSTITUTION

Journal Article · Tue Jul 01 04:00:00 EDT 1980 · Journal of Chemical Physics

OSTI ID:993848

Selwyn, G S; Johnston, H S

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 +}.

• Research Organization: Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
• Sponsoring Organization: Materials Sciences Division
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 993848
• Report Number(s): LBL-11234
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 7 Vol. 74; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
99 GENERAL AND MISCELLANEOUS
ABSORPTION
ABSORPTION SPECTRA
BENDING
BOND ANGLE
EXCITED STATES
ISOTOPIC EXCHANGE
NITROUS OXIDE
QUANTUM NUMBERS
SPECTRAL SHIFT
TEMPERATURE DEPENDENCE
VIBRATIONAL STATES
WAVELENGTHS