15min:

J. SCOTT ROBINSON, KEI-ICHI NAMIKI, D. M. GOODRIDGE AND T. C. STEIMLE, Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287.

High resolution optical spectroscopic studies of gas-phase chromium mononitride, CrN, and vanadium mononitride, VN, using molecular beam techniques have been performed. The R_ee(0.5) branch feature of the (0,0)A⁴_3/2-X^4-_1/2 band system for ⁵²CrN was recorded as a function of the static electric field in the range 1.2 - 2.0 kV/cm. The resultant Stark shifts were analyzed to produce permanent electric dipole moments of 2.31(4)D and 5.41(2)D for the ground X^4-_1/2 and excited A⁴_3/2 states, respectively. The P_e(1), F'' = 2.5 feature of the (0,0) D³₀-X³₁ band system for ⁵¹V¹⁴N (I=3.5) was also recorded as a function of static electric field in the range .4 - 1.2 kV/cm. The permanent electric dipole moments derived from a least squares analysis of the Stark shifts were 3.07(1)D for the ground X³₁ state and 6.15(3)D for the excited D³₀ state.

The ⁵²Cr¹⁴N (I=1) hyperfine structure was determined from the analysis of 12 components of the lowest pure rotational levels using the pump/probe microwave-optical double resonance technique. The resulting parameters are (in cm^-1) B''=.62387360(74), B'=.6060(1), \gamma''=.0070050(13), \lambda''=2.611151(16), eqQ₀(¹⁴N)~=~-.000025(10), b_F(¹⁴N)~=~.0000062(34) and c(¹⁴N)~=~-.000151(92). Comparisons to other experimental work and theoretical bonding models are given\footnoteWalter~J.~Balfour, Charles~X.~W.~Qian and Chi~Zhou, J. Chem. Phys. \textbf106, 4383 (1997); James~F.~Harrison, J.~Phys.~Chem. \textbf100, 3513 (1996); Margareta~R.~A.~Blomberg and Per~E.~M.~Siegbahn, Theor.~Chim.~Acta. \textbf81, 365 (1992).. Observed trends amongst the early transition metals will be discussed.