The permanent electric dipole moment of yttrium dicarbide, YC2

Optical Stark measurements were performed on the (000)(A) over tilde (2)A(1)-(000)(X) over tilde (2)A(1) band system of yttrium dicarbide, YC2. A molecular beam sample was produced by skimming the output of a free jet supersonic expansion, which contained the reactive products of an ablated yttrium metal rod in the presence of a CH4/argon mixture. The permanent electric dipole moments, mu, for the (000) (X) over tilde (2)A(1) and (000)(A) over tilde (2)A(1) states were determined to be 6.38(3) D and 7.09(6) D, respectively. A comparison with isovalent YO and YS, theoretical predictions, and a simple molecular orbital correlation diagram is presented. (C) 2001 American Institute of Physics.