The rovibrational spectrum of Difluoroethyne F-CC-F: A combined high resolution infrared and AB initio study

Pllti

368

THE ROVIBRATIONAL HIGH RESOLUTION

SPECTRUM INFRARED

H. Biirger, W. Schneider,

OF DIFLUOROETHYNE

A COMBINED

AND AB INITIO STUDY

S. Sommer and W. Thiel

FB 9, Universitat-GH,

W-5600 Wuppertal

Gas phase IR spectra

of the short-lived

have been recorded

F-C-C-F:

with a resolution

1, Germany

difluoroethyne

molecule,

of ca. 0.004 cm-' in the region of the

~‘3 band (vasCF, Ci, -1350 cm-') and the ~'2 t v3 band (vs t vasCF, cm-I).

Furthermore,

with ~4 (&"trans",

the (VI - v5) difference

and rotational

tional

states obtained.

parameters

of the ground

and hot bands

Ab initio calculations

and all singly excited of the harmonic

at the SCF and MP2 levels employing

been performed; Theoretical

band (see figure)

ZL, -2150

Ilg, -260 cm-') and v5 (6"cis", IIu, -280 cm-') have been

studied

force fields

F-C-C-F,

they successfully

and experimental

guided

molecular

different

the experimental

parameters

vibra-

and anharmonic

basis sets have investigation.

will be presented

and com-

pared.

R(J"1

J"=ll Cl(J")

1 2160

I

FCCF. v, -us I

2170 cd

I

I 2180