Extended Analysis of the Rotational Spectrum of HCCF

Abstract

The microwave spectrum of fluoroacetylene (HCCF) has been measured in the frequency region 35 -260 GHz. Rotational constants of the ground state and rotational as well as rotation-vibrational interaction constants of several excited states of the C - C - H (ν4) and the C - C - F (ν5) bending vibrations have been obtained.

The Rotational Spectrum of Fluoroethyne (HCCF) Revisited

“…Our reinvestigation revealed that the value of H 0 cannot be determined from our experimental data (neither from those obtained in our former investigation (19) nor from those of the present one), since its contribution to the measured frequencies is in the order of the measurement errors. This is a result of its smallness (the value of H 0 obtained by Dore et al (27) is only 0.00020(3) Hz), its J -dependence, and the range of our data.…”

“…A most recent MMW-and subMMW-study on the rotational spectrum of the vibrational ground state carried out by Dore et al (27) revealed a noticeable discrepancy between the newly determined value of the 6th order centrifugal distortion constant H 0 and the value previously published by us (19).…”

“…This is a result of its smallness (the value of H 0 obtained by Dore et al (27) is only 0.00020(3) Hz), its J -dependence, and the range of our data. Thus our formerly (19) presented value of −0.30(4) Hz for this constant was obviously incorrect, so that the whole set of constants (B 0 , D 0 , and H 0 ) seems to be questionable.…”

“…In Table 2 the results of three spectroscopic investigations of the vibrational ground state are compared: Those of the present one, those of our former one (19), and those published by L. Dore et al (27. ).…”

“…For that reason, we decided to reinvestigate the rotational spectrum of fluoroethyne in order to check and to improve the data given in (19). Contrary to our former investigation, our present work also comprises the lowest vibrational streching mode ν 3 .…”