Knowledge Bank

The intermodulted fluorescence spectrum of the $000-000A2\Pi -X2\pi +$ hand system of $CaOH2$ has been recorded in the presence of a de electric field. The low rotational levels of the $A2\Pi 3/2$ state are expected to have a first order Stark shift, yet no significant splitting of the $P2(2,5)+Q2(1,5)$ line was observed at the maximum obtainable de field stength of $-200V/cm$. This observation establishes an upper limit of the permanent electric dipole moment of for the $A2\Pi$ state, which is substantially less than the equivelent states of the alkaline earth monohalides. At the maximum obtainable resolution of the IMF spectrum ($-70$ MHz FWHM) no evidence of proton magnetic hyperline spliting was observed. These observations are consistent with a recent ab initio results which predict $\mu (A2\Pi ).5D,\mu (X2\Sigma +)=.9D$ and are also consistent with our failure to detect the microwave optical double resonance signal. Simple models that have been successfully used to predict the dipole moments of the alkaline earth monohalides appear not to work for the monohydroxides