Hyperfine interactions in the ground states of titanium monoxide and mononitride

A comparative study of the hyperfine interactions in the X ²Σ⁺ state of TiN and the X ³Δ state of TiO has been performed. The ⁴⁸Ti¹⁴N(I=1) hyperfine structure was determined from the analysis of 19 components of the N=1-0 and N=2-1 pure rotational transitions recorded using the pump/probe microwave-optical double resonance technique. The ⁴⁷Ti(I=5/2) hyperfine structure of X ²Σ⁺ TiN was determined from an analysis of the high resolution optical spectrum of the (0,0) A ²Π_3/2-X ²Σ⁺ band system. The resulting parameters are (in MHz) B(⁴⁸Ti¹⁴N) =18 589.3513(13), D(⁴⁸Ti14N)=0.026 31(18), γ(⁴⁸Ti ¹⁴N)=-52.2070(13), b_F(N) =18.480(3), c(N)=0.166(7), eQq₀(N)=-1.514(8), C¹(N)=0.0137(12), b_F( ⁴⁷Ti) =-558.8(11), c(⁴⁷Ti)=-15(5), and eQq ₀(⁴⁷Ti)=62(16). An analysis of the (0,0) band of the B ³Π-X ³Δ system of ⁴⁷Ti¹⁶O produced the X ³Δ hyperfine parameters (in MHz): a( ⁴⁷Ti) =-54.7(21), (b_F+2c/3)(⁴⁷Ti)=-231.6(60), and eQq₀(⁴⁷Ti)=-49(31). An interpretation based upon the predicted nature of the bonding in TiO and TiN is given.