Radiofrequency, centimeter-wave, millimeter-wave, and infrared spectra of SiHF3: Investigation of the ground, v(4)=1, and v(6)=1 vibrational states

The present paper deals with the analysis of the microwave, millimeter-wave , and infrared spectra of (SiHF3)-Si-28, ill its ground, upsilon(6) = 1 and upsilon(4) = 1 excited states. The former was observed up to 1055 GHz lead ing to the determination of one octic centrifugal distortion constant, L-j, = -0.0749(55) mu Hz. Furthermore the (k/H/k +/- 6) interaction term /h(3,G S)/ = 1.1032(70) mHz has been fitted from splittings of six K = 3 lines. Th e excited states have been regarded as isolated ones. This enabled fits acc ording the Q-, D-, and QD-reduction schemes proposed by E. I. Lobodenko, O. N. Sulakshina, V. I. Perevalov, and VI. G. Tyuterev, (J. Mel. Spectrosc. 1 26, 159-170 (1987)) and further developed by J. K. G. Watson, C. Gerke, H. Harder, and K. Sarlia, (J. Mel. Spectrosc. 187, 131-141 (1997)) and Harder (J. Mel. Spectrosc. 194, 145 (1999)), A multiple fit analysis was performed confirming, the assumption that the excited states are not affected by int ervibrational resonances. Finally the millimeter spectrum of (SiHF3)-Si-29, and (SiHF3)-Si-30, in their ground state was also measured up to 460 GHz a nd accurate rotational and centrifugal distortion parameters were derived. (C) 2000 academic Press.