Landé factors for selected levels of the e <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si103.svg" display="inline" id="d1e2126"> <mml:mrow> <mml:msup> <mml:mrow/> <mml:mrow> <mml:mn>6</mml:mn> </mml:mrow> </mml:msup> <mml:mi math

We investigate the Zeeman effect in the 0-0 band of the e 6 Π –a 6 Δ system of FeH, producing the molecule at near-ambient temperatures and recording Doppler-limited laser excitation spectra, using selective detection. We provide a set of effective Landé factors for the three lowest spin components of both states, extracted from the analysis of partially-resolved Zeeman patterns seen in magnetic flux denisities of 0.4 –0.7 T. Landé factors in the upper state show strong variations with parity, unlike the lower state level, which is close to having a single electronic configuration. Landé factors for two Fe(I) lines at 18611.635 cm − 1 and 19573.056 cm − 1 , recorded for magnetic flux density calibration, have been refined in the process. • Laser excitation spectra were collected from selected e 6 Π - a 6 Δ transitions of FeH in the presence of an applied magnetic flux density. • Landé factors for the associated rotational levels were obtained. • A perturbation in one spectrum was tentatively attributed to a Zeeman-induced interaction between the a 6 Δ 9/2 v=0 J=6.5 and X 4 Δ 7/2 v=1 J=7.5 levels. • Landé factors for three levels of atomic iron were improved.