Units of length and angle

Geometric lengths and angles are in units defined by:

UNITS
 length Angstrom / Bohr
 angle Degree / Radian
end

Angstrom and Bohr, respectively Degree and Radian, are recognized strings. Each of the subkeys is optional, as is the key UNITS itself. Defaults: Angstrom for lengths, and Degree for angles.

The position of the key UNITS in input is significant as regards the evaluation of expressions (see the paragraph on constants and functions below). In other respects its position plays no role. To avoid mistakes one should place units as early as possible in input (if at all).