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Two transitions of tungsten sulfide (WS) near 13,100 cm−1, the (0,0) band of the [13.10]1 – X 3Σ−0 + transition and the (0,0) band of the [15.30]1 – X 3Σ−1 transition, have been recorded at high resolution using intracavity laser absorption spectroscopy with a Fourier-transform spectrometer used for detection (ILS-FTS). The WS molecules were produced in the plasma discharge formed by applying 0.70–0.80 A of a discharge current from a pulsed DC plasma generator to a tungsten-lined copper hollow cathode. The reaction took place in the presence of Ar (~70 %), H2 (~30 %), and CS2 (~0.1 %) gases at a total pressure of approximately 2 torr. Lines for all four abundant isotopologues of WS, 182W32S, 183W32S, 184W32S, and 186W32S, were measured and a rotational analysis was performed using PGOPHER. A constrained parameters approach was used to maintain expected mass relationships among isotopologues. This analysis increases the number of observed rotational levels from J ~ 30 to J ~ 100 for both excited states, allowing an increase in precision of spectroscopic constants. The new analysis of the [15.30]1 – X 3Σ−(1) transition enabled the reduced uncertainty in the previously determined value for the splitting of the 0+ and 1 Ω-components of the X 3Σ− ground state. Also presented in this work is an expansion upon our earlier deperturbation analysis involving the [15.30]1 state to include the v′ = 2 vibrational level, which is perturbed by the v′ = 4 vibrational level of the [14.26]0+ state.
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This content will become publicly available on April 14, 2026
A new electronic transition in vanadium fluoride, VF
The red-degraded [12.7]5Δ–X5Δ (0–0) band of gas-phase vanadium fluoride at 789 nm has been recorded by laser excitation spectroscopy and represents only the second reported rotational analysis of an electronic transition of VF. A hollow cathode discharge source was employed, with laser-induced fluorescence detected via the [12.7]5Δ–X5Δ (0–1) band. All five main (∆Ω = 0) subbands were identified, each containing only P and R branches, as expected in a parallel (∆Λ = 0) transition. The upper state displays the effects of strong local perturbations. Molecular constants describing the X5Δ (v = 0 and 1) levels and the [12.7]5Δ (v = 0) level were determined from least-squares fits using an effective Hamiltonian written in a Hund’s case (a) basis. The equilibrium rotational constant of the ground state was determined to be Be = 0.38324(89) cm−1, which yields a molecular bond length of Re = 1.7829(21) Å.
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- Award ID(s):
- 2100542
- PAR ID:
- 10648774
- Publisher / Repository:
- AIP Publishing
- Date Published:
- Journal Name:
- The Journal of Chemical Physics
- Volume:
- 162
- Issue:
- 14
- ISSN:
- 0021-9606
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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