`DIATOMIC`[`,`DEGREE=n][`,`MASS=m][`,`PRINT=p]

The data are fitted to a polynomial of degree (default is number
of points minus 1, ie interpolation), and spectroscopic constants
calculated using reduced mass expressed in u. Note that it is
possible to constrain which bond lengths are used through the use of
the `RANGE` subcommand.

molpro@molpro.net 2019-03-20