  Calculations are reported on the rotation-vibration energy levels of the
arsine molecule with associated transition intensities. A potential energy
surface (PES) obtained from \textit{ab initio} electronic structure
calculations is refined to experimental data, and the resulting energy levels
display sub-wavenumber accuracy for all reliably known $J=0$ term values under
6500 cm$^{-1}$. After a small empirical adjustment of the band centres, our
calculated ($J=1-6$) rovibrational states reproduce 578 experimentally derived
energies with a root-mean-square error of 0.122 cm$^{-1}$. Absolute line
intensities are computed using the refined PES and a new dipole moment surface
(DMS) for transitions between states with energies up to 10~500 cm$^{-1}$ and
rotational quantum number $J=30$. The computed DMS reproduces experimental line
intensities to within 10\% uncertainty for the $\nu_1$ and $\nu_3$ bands.
Furthermore, our calculated absorption cross-sections display good agreement
with the main absorption features recorded in Pacific Northwest National
Laboratory (PNNL) for the complete range of $600-6500$ cm$^{-1}$.
