The infrared spectrum of KH

Abstract

Reported here is the first observation of the infrared spectrum of KH. Fundamental bands and first hotbands of the 39KH and 41KH isotopic forms were measured at high resolution using a diode laser based spectrometer. An ac glow discharge through potassium vapor and hydrogen gas was used to produce KH. A combined isotopic Dunham coefficient analysis was used to fit all the spectra, with the Dunham coefficients for 39KH coming out as Y10=985.6714(30) cm−1, Y20=−14.9013(10) cm−1, Y01=3.416 40(10) cm−1, Y11=−0.085 313(26) cm−1, Y21=5.41(60)×10−4 cm−1, Y02=−1.6354(36)×10−4 cm−1, Y12=1.13(10)×10−6 cm−1, Y03=7.6(8)×10−9 cm−1, (quoted at 2σ error limits). A bond length of 2.241 152(16) Å and a Dunham corrected value for ωe of 986.0505(30) cm−1 are obtained. The pressure broadening of KH by H2 and the chemistry of KH formation in the glow discharge plasma are also discussed.