Journal of Chemical Physics, Vol.111, No.3, 1008-1016, 1999
The vibrational energy pattern in acetylene. V. (C2H2)-C-13
A total of 134 vibrational levels with assigned rotational structure have been gathered in the ground electronic state of (C2H2)-C-13. Most of these measurements are updated or new compared to the previously published data. Altogether, they cover the range up to 23 670 cm(-1). 118 out of the 119 levels observed below 13 000 cm(-1) have been simultaneously fitted using the so-called cluster model, already used to deal with the vibrational energy levels in other isotopomers of acetylene [El Idrissi , J. Chem. Phys. 110, 2074 (1999), and references therein]. Twenty-nine vibrational constants have been determined, including the off-diagonal parameters K-3/245, K-1/244, K-1/255, K-11/33, K-14/35, and r(45), with a rms of the fit equal to 0.52 cm(-1). The same three constants of the motion as in (C2H2)-C-12 emerged, N-s=v(1)+v(2)+v(3), N-r=5v(1)+3v(2)+5v(3)+v(4)+v(5) and k=l(4)+l(5). The energies of the levels above 13 000 cm(-1) calculated with the obtained parameters compare reasonably well with the experimental values. For all levels the predicted rotational constants compare satisfactorily with the experimental results.