Precise measurements with a compact vacuum infrared spectrometer

A 3-m vacuum grating IR spectrometer with digital recording is described. Resolution better than 0.025 cm−1 at 3000 cm−1 is demonstrated, and details are given of a fast deconvolution procedure by which the resolution is enhanced to near 0.010 cm−1. The grating drive incorporates a Merton nut, which facilitates the measurement of highly precise wave numbers. Lines in the 1201 band of N2O near 4630 cm−1 have been measured and agree within an average of ±0.0004 cm−1 with interferometric values.