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 2Π3/2–X 2Σ+ band system. The resulting parameters are (in MHz) B(48Ti14N)=18 589.3513(13), D(48Ti14N)=0.026 31(18), γ(48Ti14N)=−52.2070(13), bF(N)=18.480(3), c(N)=0.166(7), eQq0(N)=−1.514(8), CI(N)=0.0137(12), bF(47Ti) =−558.8(11), c(47Ti)=−15(5), and eQq0(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), (bF+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.

The permanent electric dipole moments of the ground, and the low-lying excited electronic states of platinum monocarbide, PtC, platinum monoxide, PtO, and platinum monosulfide, PtS, were measured using a molecular beam optical Stark spectroscopic scheme. The determined values were (in Debye): PtO(X 3Σ−) 2.77(2); PtO(A 1Σ+) 1.15(4); PtS[X(Ω=0)] 1.78(2); PtS[B(Ω=0)] 0.54(6); PtC(X 1Σ+) 0.99(5); and PtC(A 1Π) 2.454(3). These results, along with the previous results for PtN(X 2Π1/2) 1.977(9); PtN(d 4Π1/2) 1.05(9) [J. Chem. Phys. 102, 643 (1995)], are used as a basis for a discussion of the nature of the electronic states.

The permanent electric dipole moments of CaOH and SrOH in their X 2Σ+, A 2Π3/2, A 2Π1/2, and B 2Σ+ states have been measured using the technique of supersonic molecular beam optical Stark spectroscopy. For CaOH the values obtained were μ(X 2Σ+)=1.465(61)D, μ(A 2Π1/2)=0.836(32)D, μ(A 2Π3/2)=0.766(24)D, and μ(B 2Σ+)=0.744(84)D, while for SrOH the values were μ(X 2Σ+)=1.900(14)D, μ(A 2Π1/2)=0.590(45)D, μ(A 2Π3/2)=0.424(5)D, and μ(B 2Σ+)=0.396(61)D. The results are compared with values from a recent ab initio calculation for CaOH and with the predictions of a semiempirical electrostatic polarization model.

Platinum nitride, PtN, was identified in the supersonic coexpansion of a laser ablation generated platinum vapor and ammonia by laser induced fluorescence spectroscopy. The intense blue band system was assigned as the (0,0) d 4Π1/2–X 2Π1/2 transition with the determined spectroscopic fine parameters being (in cm−1):T00=18586.3608(28), B″=0.4541(7), (p+2q)″=0.1219(15), B′=0.4164(7), and (p+2q)′=0.2039(8). The Stark shifts and splitting were analyzed to produce ground and excited electronic state values for the permanent electric dipole moment of 1.977(7)D and 1.0(1)D, respectively. The splitting in the field free spectrum for the 195Pt isotopomer was analyzed to produce magnetic hyperfine parameters (in cm−1) h1/2″= 0.0639(30), h1/2′ = 0.1571(36), d′=−0.0979(7), and d″=−0.0034(15). A sophisticated ab initio calculation of the physical properties of the low-lying states was performed. The experimental results are generally consistent with the ab initio predictions that the band system is the (0,0) d 4Π1/2–X 2Π1/2 transition. A discussion of the nature of the electronic states is given.

The first successful pump/probe microwave-optical double resonance experiment using a laser ablation/reaction scheme for molecular beam production has been performed. Pure rotational transitions at frequencies up to 52 GHz have been recorded for the transient refractory compounds YF, YO, and SrOH at a resolution of <30 kHz [full-width at half- maximum (FWHM)]. The observed three lowest pure rotational transition frequencies of YF (X 1Σ+) were analyzed to produce an improved set of rotational constants, B=8683.6156(11) MHz and D=0.007 521(74) MHz. The three lowest pure rotational transitions of SrOH (X 2Σ+) were analyzed to give the spectroscopic parameters (in MHz), B=7470.8180(4), D=0.006 25(3), γ=72.706(1), γD=−0.0021(2); bF (H)=1.713(2) and c (H)=1.673(5). The proton magnetic hyperfine interactions were interpreted in terms of a molecular orbital description for the X 2Σ+ state.