A contribution to the microwave spectrum and structure of phenylacetyleneq

We report a reinvestigation of the rotational spectrum of phenylacetylene (PhA, ethynylbenzene) by molecular beam Fourier transform microwave spectroscopy measuring the spectra of 39 isotopomers. All atomic positions could be singly substituted or in combinations with others. The hyperfine structure of the deuterated isotopomers could be partly resolved and evaluated. The inertial moments were employed to calculate the molecular structure using all recent methods, which take account of the rovibrational contributions to these moments as well as several different weighting schemes of the least-squares procedure. The experimental structure is confronted with the structures obtained by several purely theoretical quantum-mechanical calculations including the most adequate for the present task, the CCSD(T)/CBS method. q 2004 Elsevier B.V. All rights reserved