Rovibrational levels of low-lying electronic states of the diatomic molecule PtH are computed using non-relativistic wavefunction methods and a relativistic core pseudopotential. Dynamical electron correlation is treated at the coupled-cluster with single and double excitations and a perturbative estimate of triple excitations level, with basis-set extrapolation. Spin-orbit coupling is treated by configuration interaction in a basis of multireference configuration interaction states. The results compare favorably with available experimental data, especially for low-lying electronic states. For the yet-unobserved first excited state, Ω = 1/2, we predict constants including Te = (2036 ± 300) cm-1 and ΔG1/2 = (2252.5 ± 8) cm-1. Temperature-dependent thermodynamic functions, and thermochemistry of dissociation, are computed from the spectroscopic data. The ideal-gas enthalpy of formation is ΔfH298.15o(PtH) = (449.1 ± 4.5) kJ mol-1 (uncertainties expanded by k = 2). The experimental data are reinterpreted, using a somewhat speculative procedure, to yield the bond length Re = (1.5199 ± 0.0006) Å.
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http://dx.doi.org/10.1063/5.0145567 | DOI Listing |
J Phys Chem A
January 2025
Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States.
The cyano-cyclopentadiene molecule (CN-CH) has attracted significant interest since its detection in the interstellar medium, but the radical (CN-CH) and anionic (CN-CH) forms of cyano-cyclopentadiene have not been studied. The cyano-cyclopentadienyl radical (CN-Cp) has a strong dipole moment, rendering it an ideal system for vibrational and rotational spectroscopy. We report an investigation of the cryogenically cooled cyano-cyclopentadienide anion (CN-Cp) using high-resolution photoelectron imaging, photodetachment spectroscopy, and resonant photoelectron imaging.
View Article and Find Full Text PDFJ Chem Phys
January 2025
School of Chemistry, University of St Andrews, North Haugh, Fife, St Andrews KY16 9ST, United Kingdom.
Two synchrotron-based studies on 4H-pyran-4-thione, photoelectron spectroscopy and vacuum ultraviolet (VUV) absorption spectra were performed. A highly resolved structure was observed in the photoelectron spectrum (PES), in contrast to an earlier PES study, where little structure was observed. The sequence of ionic states was determined using configuration interaction and coupled cluster methods.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China.
High-level multireference configuration interaction plus Davidson correction (MRCI + Q) calculation method was employed to determine the potential energy curves (PECs) of 10 Λ-S states, which come from the first and second dissociation channels of the SbP molecule, as well as 34 Ω states considering the spin-orbit coupling (SOC) effect. By solving the Schrödinger equation for nuclear motion, spectroscopic constants for the ground state XΣ and low-lying excited states were obtained and compared with experimental data. The excellent agreement indicates the reliability of our calculations.
View Article and Find Full Text PDFJ Comput Chem
January 2025
Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China.
Various electronically excited states and the feasibility of direct laser cooling of SH, SeH, and TeH are investigated using the highly accurate ab initio and dynamical methods. For the detailed calculations of the seven low-lying Λ-S states of SH, we utilized the internally contracted multireference configuration interaction approach, considering the spin-orbit coupling (SOC) effects. Our calculated spectroscopic constants are in very good agreement with the available experimental results.
View Article and Find Full Text PDFJ Comput Chem
January 2025
Chemistry and Forensic Science, School of Natural Sciences, University of Kent, Canterbury, UK.
Magnesium-containing molecules, including MgCH, MgCH, and MgCH, have been detected in the interstellar medium, largely facilitated by their high dipole moments. However, despite great efforts, MgCH species remain elusive. Given the challenges in obtaining experimental data for these molecules, theoretical studies play a crucial role in guiding their detection.
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