Article
Mass-independent Dunham analysis of the [13.8] Ω = 3/2 − X 2Π3/2 transition of platinum monochloride, PtCl, observed by intracavity laser spectroscopy: Periodic trends in the M+X− bonding model (M = Ni, Pt; X = F, Cl)
Journal of Molecular Spectroscopy
(2019)
Abstract
The first electronic transition of platinum chloride, PtCl, observed at high resolution has been recorded in absorption using Intracavity Laser Spectroscopy (ILS). The PtCl molecules were produced in a current-regulated RF discharge formed when 0.30–0.60 A was applied to a Pt-lined Cu hollow cathode in a ∼1 Torr Ar/He sputter gas mixture, with a trace amount of CCl4 as the chloride source. The hollow cathode was located within the resonator cavity of either a tunable DCM dye laser operated over the 14,500–16,500 cm−1 range or a Ti:Sapphire laser operated over the 12,890–12,990 cm−1 and 13,255–13,365 cm1 ranges. Effective absorption path lengths ranging from 0.6 to 2.0 km were utilized with the ILS method. Eight band systems were identified and rotationally analyzed as the (0,2), (0,1), (3,0), (4,0), (5,0), (6,0), (6,1), and (7,1) vibrational bands of the [13.8] Ω = 3/2 − X 2Π3/2 transition of PtCl. The vibrational assignment was confirmed through isotopologue shift analysis. The ILS data and millimeter- and submillimeter-wave data reported by Okabayashi et al. (2012) were fit to a mass-independent Dunham-type Hamiltonian using PGOPHER. Pt-isotope dependent deviations in the Dunham model were observed in Y″01(Be″), Y′01(Be′), and Y′00(Te′) and treated using field-shift parameters, and these parameters are compared to the reported field-shift effects for other 5d transition metal diatomics. The excited state molecular constants determined in this study are consistent with those of the (4) 3/2 state in the computational study by Zou and Suo (2016). The electronic transitions of NiF, NiCl, and PtF analogous to the [13.8] Ω = 3/2 – X 2Π3/2 transition of PtCl have been studied both theoretically and experimentally. The vibrational force constants and relative bond lengths for the MX (M = Ni, Pt; X = F, Cl) molecules suggest that Ni and Pt form similar MX bonds, with NiX bonds being slightly stronger, but a large effect is observed for halogen substitution, with MF force constants being more than twice as large as the corresponding MCl values.
Disciplines
Publication Date
May, 2019
DOI
https://doi.org/10.1016/j.jms.2019.03.002
Citation Information
Jack C. Harms, Ji Wu, Leah C. O'Brien and James O'Brien. "Mass-independent Dunham analysis of the [13.8] Ω = 3/2 − X 2Π3/2 transition of platinum monochloride, PtCl, observed by intracavity laser spectroscopy: Periodic trends in the M+X− bonding model (M = Ni, Pt; X = F, Cl)" Journal of Molecular Spectroscopy Vol. 359 (2019) p. 6 - 15 Available at: http://works.bepress.com/james-obrien/16/