  The emission of the 4.438-MeV gamma-ray line in proton inelastic scattering
off 12C has been investigated in detail. The correlated scattering and emission
process is described independently for the direct reaction mechanism and for
the compound-nucleus (CN) component. The inelastic scattering process for
direct reactions is treated with a coupled-channels nuclear reaction code,
while the CN component is described as a superposition of separate resonances
with definite spin and parity, treated with the angular momentum coupling
theory. The calculations are compared to a comprehensive data set on measured
line shapes and angular distributions in the proton energy range E_p = 5.44 -
25.0 MeV. In the range E_p ~ 12 - 25 MeV a good agreement is obtained in
calculations assuming direct reactions with only a negligible part of CN
reactions. At lower energy, the data are reproduced by incoherent sums of the
direct component with typically one CN resonance. Based on these results, the
prospectives for line shape calculations applied to solar flares and gamma-ray
emission in proton radiotherapy are discussed.
