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We report the observation and analysis of a new electronic transition in gas-phase vanadium hydride (VH), identified as the C′5Δ–X5Δ (1,0) band with an origin at 14,015 cm− 1 (714 nm). The spectrum was recorded by laser excitation spectroscopy, with laser-induced fluorescence detected to the X5Δ (v =1) level. Dispersed fluorescence measurements enabled a detailed characterization of the vibrationally excited ground state, yielding a vibrational interval of ΔG1/2 = 1606.6(2) cm− 1 . Despite the presence of significant local perturbations—particularly in the Ω =0 and 1 spin components of the C′5Δ state—a full rotational analysis of the spectrum using a Hund’s case (a) Hamiltonian was achieved. Spectroscopic constants including rotational, spin–orbit, spin–rotation, and Λ-doubling parameters are reported for both the new C′5Δ state and the X5Δ (v = 1) level. Additionally, we observed a small local perturbation in the X5Δ₁ (v =1) level near J =9, attributed to homogeneous spin–orbit and heterogeneous L-uncoupling interactions with the previously analyzed A5Π (v =0) state. An X5Δ ~ A5Π coupled Hamiltonian was used to model this perturbation and yielded interaction parameters roughly consistent with semi-empirical estimates. This work represents only the second analyzed spectroscopic transition of gas-phase VH.
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This content will become publicly available on February 1, 2026
Rotational analyses of two transitions of WS near 13,100 cm−1, and further deperturbation analysis of the [15.30]1 – X 3Σ−0+ transition
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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- Award ID(s):
- 1955773
- PAR ID:
- 10633219
- Publisher / Repository:
- Elsevier
- Date Published:
- Journal Name:
- Journal of Molecular Spectroscopy
- Volume:
- 408
- Issue:
- C
- ISSN:
- 0022-2852
- Page Range / eLocation ID:
- 111999
- Subject(s) / Keyword(s):
- Tungsten sulfide Intracavity laser spectroscopy Isotopologues Electronic structure Molecular constants of WS Perturbation analysis
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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