We calculate new line lists and opacities for the F^4Δ_i-X^4Δ_i transition of FeH. The 0-0 band of this transition is responsible for the Wing-Ford band seen in M-type stars, sunspots and brown dwarfs. The new Einstein A values for each line are based on a high level ab initio calculation of the electronic transition dipole moment. The necessary rotational line strength factors (Hönl-London factors) are derived for both the Hund's case (a) and (b) coupling limits. A new set of spectroscopic

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... tants were derived from the existing FeH term values for v=0, 1 and 2 levels of the X and F states. Using these constants extrapolated term values were generated for v=3 and 4 and for J values up to 50.5. The line lists (including Einstein A values) for the 25 vibrational bands with v≤4 were generated using a merged list of experimental and extrapolated term values. The FeH line lists were use to compute the molecular opacities for a range of temperatures and pressures encountered in L and M dwarf atmospheres. Good agreement was found between the computed and observed spectral energy distribution of the L5 dwarf 2MASS-1507.