The VN molecule has been produced in a molecular beam apparatus using a laser vaporization source and its D 3Π–X 3Δ(0,0) band has been studied by laser-induced fluorescence at low (∼0.1 cm−1) and sub-Doppler resolution (∼0.004 cm−1). Lifetimes of single rotational levels of the D 3Π0 component have been measured and interpreted. Rotational, fine, and hyperfine structures in six of the nine subbands possible for a 3Π ← 3Δ transition have been recorded. Both states exhibit a rapid transition from case (a) → case (b) coupling cases, manifested by reversals in the Landé patterns of the hyperfine structure. The data have been reduced to a set of 35 molecular constants using a modified case (aβ) effective Hamiltonian in which two additional magnetic hyperfine parameters are required for each state. The distortions in the hyperfine structure are due almost entirely to second-order spin–orbit interaction between states arising from the same configuration. Analysis of the derived parameters indicates that the X 3Δ state is well represented by the single electron configuration ...8σ2 3π4 9σ1 1δ1, in which the 9σ molecular orbital (MO) is a V 4s–4p hybrid (88% V 4s) and the 1δ MO is a pure V 3d orbital; the dominant configuration for the D 3Π state is ...8σ2 3π4 1δ1 4π1, in which the 4π MO is an antibonding orbital composed of at most 82% V 3dπ. The isoconfigurational a 1Δ and e 1Π states are calculated to lie 3390 and 2200 cm−1 above their respective high spin companions. The lambda doubling in the D 3Π0 component has been interpreted in terms of spin–orbit interactions with the B 3Σ− and d 1Σ+ states, both states arising from the ...8σ2 3π4 1δ2 configuration; the d 1Σ+ state is known [Simard, Masoni, and Hackett, J. Mol. Spectrosc. 136, 44 (1989)] to lie 102 cm−1 above D 3Π0, while the B 3Σ− state probably lies about 8000 cm−1 below.

The permanent electric dipole moments and magnetic hyperfine interactions of ruthenium mononitride, RuNThe permanent dipole moment of TiN in its X 2l; + and A 2l; states has been determined from the complete resolution of the first-and second-order Stark splitting of the Q21 ( 1. 5) + R2 (0.5) line of the (0,0) band of the A 2II_X 2l; + system. Values of 3.56 ± 0.05 D (20-) and 4.63 ± 0.04 D (20-) have been derived for the X and A states respectively, from least-squares fits to plots of Stark splitting vs electric field strength. Electric fields up to 12 kV /cm have been employed avoiding voltage breakdown. The zero-field spectrum shows resolution of the nuclear magnetic hyperfine structure of the 47 TiN and 49 TiN isotopes. This hyperfine structure is that of the ground X 2l; + state only and is shown to follow closely the coupling case bps. The value ofthe Fermi contact parameter is -570 MHz which implies a 4s occupation of the 90-molecular orbital (MO) of 72 %. The results are compared with calculated and available experimental values for early first-row transition metal oxides and nitrides.7012

The (0,0,0)–(0,0,0) band of the B̃ 2Σ+–X̃ 2Σ+ system of three isotopomers of yttrium imide (Y14NH, Y15NH, and Y14ND) has been studied by laser-induced fluorescence in a molecular beam apparatus. Rotational, fine, and nuclear magnetic hyperfine structures have been resolved and analyzed. The B̃ 2Σ+(0,0,0) state of Y14NH, Y14ND, and Y15NH is severely perturbed below J=30.5 by eight, three, and two vibronic states, respectively. Although, the nature of these perturbing states can only be speculated upon, their symmetries are either Σ2 or Π2, and this has made it possible to deperturb the B̃ 2Σ+ state successfully. The spectra can be reproduced within 140 MHz (0.0047 cm−1). The analyses confirm that the molecule is linear in both states with the nuclear arrangement Y–N–H. The bond lengths in the ground X̃ 2Σ+ state and the B̃ 2Σ+ state have been derived to be rY–N=1.877 57(13) Å, rN–H=1.0067(10) Å, and rY–N=1.8839(43) Å, rN–H=1.242(30) Å, respectively. The results are compared with the values of ab initio calculations on YNH and YN, and the experimental data on YN and YO. The atomic character of the unpaired electron in the ground state is 58% Y + 5s and 42% Y + 5p. The electron configurations for the ground X̃ 2Σ+ state and the B̃ 2Σ+ state are discussed and compared with ab initio calculations whenever possible.

The (0,0,0)–(0,0,0) bands of the Ã 2Π–X̃ 2Σ+ and Ã″ 2Π1/2–X̃ 2Σ+ systems of three isotopomers of yttrium imide (Y14NH, Y15NH, and Y14ND) have been studied by laser-induced fluorescence in a molecular beam apparatus. Rotational, fine, and nuclear magnetic hyperfine structures have been resolved and analyzed. The previously studied B̃ 2Σ+−X̃ 2Σ+ (0,0,0)–(0,0,0) bands of the three isotopomers have been reanalyzed. Global fits of all observed bands, in which the ground state has been fitted to a Hamiltonian model, while the excited states have been represented by term values, have been performed for the three isotopomers. Subsequently, the individual bands have been fitted. The ground state parameters have been fixed at the values obtained in the global fits, while the upper states have been fitted to the Hamiltonian models. The (0,0,0) Ã 2Π state of Y14NH, Y15NH, and Y14ND is severely perturbed. Even though the nature of these perturbing states can only be speculated upon, the introduction of effective perturbers made it possible to deperturb the state successfully. The Ã″ 2Π1/2 state is unperturbed. The spectra can be reproduced to better than 120 MHz (0.004 cm−1). The analyses confirm that the molecule is linear in all four states with the nuclear arrangement Y–N–H. The bond lengths (r0 structure) in the X̃ 2Σ+ ground state and the Ã″ 2Π1/2, Ã 2Π, and B̃ 2Σ+ excited states have been derived to be rYN=0.187785(17) nm, rNH=0.10039(14) nm; rYN=0.1927(1) nm, rNH=0.081(1) nm; rYN=0.19013(56) nm, rNH=0.1032(54) nm; and rYN=0.18848(52) nm, rNH=0.1236(46) nm, respectively. The electronic configurations for the X̃ 2Σ+ ground state and the Ã 2Π, Ã″ 2Π1/2, and B̃ 2Σ+ excited states are discussed and compared with ab initio calculations whenever possible.

Oscillatory bound-tcontinuum emission from vibrational levels v' =0-6 of the B(22f) state of InAr onto the repulsive walls of the Xi (2111,2), X2(211s,2), and A (22+) electronic states, has been measured. In the B(2Zc+) +X1 (21111,2) spectrum, the intensity extrema have been associated with particular extrema and nodes of the radial wave functions of the emitting levels, and the resulting phase vs energy information directly inverted to yield a pointwise potential for the Xi (211 i12) state. Analysis of the observed peak heights then showed that on the range 2.9-3.8 A the associated transition moment function is constant. The overlapping of the B(22+) +X2(21113,2) and B(22f)-+A (2zC_f) spectra prevents application of the above inversion procedure, but reliable estimates of these two final-state potentials were obtained by matching quantum mechanical simulated spectra with experiment. The simulations also showed that the transition moment functions associated with all three transitions are of approximately equal strength.