Laboratory measurement of the permanent electric dipole moment of gas-phase CuO in its X 2Π state

A sub-Doppler optical Stark measurement of the P1(1.5) branch feature of the A 2Σ−(v′=0)–X 2Π3/2(v″=0) subband system of gas phase copper monoxide, CuO, has been performed. The observed Stark shifts have been analyzed and a permanent electric dipole moment of 4.45±0.30 D (1σ error estimate) for the X 2Π3/2 state determined. The results are discussed in terms of the various bonding models proposed for CuO.