Document Type

Article

Abstract

The a 4Σ−–X 2Π1/2 transition of GeH has been recorded in absorption for the first time using Intracavity Laser Spectroscopy (ILS). The GeH molecules were produced in a 0.40–0.60 A DC plasma discharge inside an aluminum hollow cathode, using 500 mTorr of Ar, 100 mTorr of H2, and 200 mTorr of GeH4. This cathode is located within the resonator cavity of a Coherent Verdi™ V-10 pumped dye laser. Effective path lengths for this series of measurements using the ILS method ranged from 2 to 7 km. Spectra were calibrated using the absorption spectrum of I2 collected from an extracavity cell, the I2 transmission spectrum from Salami and Ross, J. Mol. Spectrosc. 223(1), 157 (2005) and PGOPHER’s [C. M. Western, J. Quant. Spectrosc. Radiat. Transfer 186, 221–242 (2016)] calibration feature. Differences in peak positions between calibrated experimental spectra and the reference data were on average less than ±0.002 cm−1. All eight branches expected to have appreciable intensity for the transition have been identified, and isotopologue splitting was observed in features of 5 of the 8 identified rotational branches. Molecular constants have been obtained for the a 4Σ− states of 70GeH (20.84% abundant), 72GeH (27.54% abundant), and 74GeH (36.28% abundant). The transitions were fit using PGOPHER, holding the ground state constants fixed to the values reported by Towle and Brown [Mol. Phys. 78(2), 249 (1993)]. The constants for the a 4Σ− state of 74GeH determined by the fit are T0 = 16 751.5524(13) cm−1, B0 = 6.764 912(33) cm−1, D0 = 0.459 60(17) × 10−3 cm−1, λSS = 9.7453(12) cm−1, λD = 0.468(14) × 10−3 cm−1, γ = 0.077 878(84), and γS = −0.361(77) × 10−3 cm−1.

Publication Date

May 2018

Publication Title

Journal of Chemical Physics

Volume

148

Issue

20

First Page

204306

DOI

10.1063/1.5017958

Comments

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in
The Journal of Chemical Physics

“The spin-forbidden a 4Σ- ‑ X 2Π1/2 transition of GeH detected in absorption using intracavity laser spectroscopy,” J. Chem. Phys., J. C. Harms, L. C. O’Brien, and J. J. O’Brien, 2018, 148, 204306.
and may be found at https://aip.scitation.org/doi/10.1063/1.5017958

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