INFRARED-ABSORPTION AND EMISSION-SPECTRA OF SIO

High-resolution Fourier transform infrared spectra of SiO were recorde d from two sources, the umbral region of a sunspot and a high-temperat ure laboratory cell. Rovibrational transitions in the sunspot absorpti on spectrum were measured in consecutive vibrational bands from (1, 0) to (13, 12) with J values as high as 141 for (SiO)-Si-28-O-16 (1258 l ines) and (1, 0) to (6, 5) for (SiO)-Si-29-O-16 and (SiO)-Si-30-O-16 ( 455 lines). In the lower temperature laboratory emission spectrum only 387 rotational lines in the (1, 0) to (5, 4) bands were measured excl usively for (SiO)-Si-28-O-16. The laboratory spectrum served primarily to calibrate the lines in the sunspot spectrum to absolute rest frequ encies. An improved set of Dunham constants for the (1) Sigma(+) groun d state was obtained from a global fit of a combined data set consisti ng of our IR data and all the previously reported microwave and millim eter-wave data. In addition, an internuclear potential for the (1) Sig ma(+) ground state, in the form of a parameterized modified-Morse func tion, was also obtained by fitting the data directly to the eigenvalue s of the radial Schrodinger equation.