Emission Spectroscopy and Ab Initio Calculations for TaN

Abstract

The emission spectra of TaN have been investigated in the region 3000-35 000 cm −1 using a Fourier transform spectrometer. The spectra were observed in a tantalum hollow-cathode lamp by discharging a mixture of 1.5 Torr of Ne and about 6 mTorr of N 2 . In addition to previously known bands, numerous additional bands were observed and assigned to a number of new transitions. The spectroscopic properties of the low-lying electronic states of TaN were also predicted by ab initio calculations. A 1 + state, with equilibrium constants of B e = 0.457 852 1(48) cm −1 , α e = 0.002 235 9(67) cm −1 , and R e = 1.683 099 9(88)Å, has been identified as the ground state of TaN based on our experimental observations supported by the ab initio results. The first excited state has been identified as the a 3 1 spin component at 2827 cm −1 above the ground state. To higher energies, the states become difficult to assign because of their Hund's case (c) behavior and extensive interactions between the spin components of the electronic terms. C 2002 Elsevier Science (USA)

TaN molecule as a candidate for the search for aT,P-violating nuclear magnetic quadrupole moment

“…The effective electric field is rather strong (1.5 times more than that in HfF + [14,15] and similar to other considered transition elements compounds E eff (PbF) [36] and WC [33]) but about two times 20e-2c-CCSD(T), this work 3.19 1028 3.5 Experiment, [46] 3.20 ---…”

“…which agrees well with the experimental datum [46], see table I. In calculations of the parameters under consideration we have set R(Ta-N) to 3.20 a.u.…”

“…This suggests a rather complicated electronic structure in terms of electron correlation effects. Up to now the molecule was rather poor investigated both experimentally and theoretically [44,46]. There are no experimental data about the molecule-frame dipole moment, hyperfine structure, etc.…”

Time-Reversal Symmetry Violation in Molecules Induced by Nuclear Magnetic Quadrupole Moments

“…This makes it similar to the 3 Δ 1 state of the molecule ThO. However, here calculations indicate that the σ orbital is primarily a mixture of the 6s and 5d orbitals of the heavy atom (Ta), with no admixture of the p wave reported in [46]. The closest analogue to TaN is YbF.…”

Fourier transform emission spectroscopy and ab initio calculations on NbCl

“…We have used the same computational approach as in our previous work on transition metal diatomic nitrides [10][11][12][13], oxides [14], and chlorides [4,15,16]. The ab initio calculation consists of a complete active space self-consistent field (CASSCF) calculation [17] followed by an internally contracted multireference configuration interaction (CMRCI) calculation [18], as implemented in the MOLPRO computer package [19].…”