  MOLSCAT is a general-purpose package for performing non-reactive quantum
scattering calculations for atomic and molecular collisions using
coupled-channel methods. Simple atom-molecule and molecule-molecule collision
types are coded internally and additional ones may be handled with plug-in
routines. Plug-in routines may include external magnetic, electric or photon
fields (and combinations of them). Simple interaction potentials are coded
internally and more complicated ones may be handled with plug-in routines.
  BOUND is a general-purpose package for performing calculations of bound-state
energies in weakly bound atomic and molecular systems using coupled-channel
methods. It solves the same sets of coupled equations as MOLSCAT, and can use
the same plug-in routines if desired, but with different boundary conditions.
  FIELD is a development of BOUND that locates external fields at which a bound
state exists with a specified energy. One important use is to locate the
positions of magnetically tunable Feshbach resonance positions in ultracold
collisions.
  Versions of these programs before version 2019.0 were released separately.
However, there is a significant degree of overlap between their internal
structures and usage specifications. This manual therefore describes all three,
with careful identification of parts that are specific to one or two of the
programs.
