Argon FTIR spectra between 800 and 2000 cm−1: h- and i-levels and transition probabilities

•Spectrum of atomic argon is measured using the time-resolved Fourier transform technique.•Seventy-seven previously experimentally unobserved Ar I lines have been reported.•The energies of 7i and 6h levels have been extracted from the experimental data.•Quantum defect theory calculations of the matrix elements in the 800-1200 cm−1 range are presented.

The new emission spectrum of atomic argon is measured using the time-resolved Fourier transform technique. Seventy-seven new Ar I lines in the 800-2000cm−1 range with a resolution of 0.02cm−1 are observed. The energies of 12 previously unknown 7i and 6h energy levels are extracted from the measured spectra. The probabilities of the transitions between the observed levels are calculated.