The experimental data was reported by
(1) T. A. Cooper, H. W. Kroto, J. F. Nixon, and O. Ohashi, 1980, J. Chem. Soc., Chem. Commun. 90, 333; by
(2) L. Bizzocchi, C. Degli Esposti, and P. Botschwina, 2000, J. Chem. Phys. 113, 1465; and by
(3) L. Bizzocchi, S. Thorwirth, H. S. P. Müller, F. Lewen, and G. Winnewisser, 2001, J. Mol. Spectrosc. 205, 110.
The dipole moment has been measured in (1).