The input chemical formula should follow a certain format.
- Acceptable formats: 'Sr Ti1 O3', 'Sr1. Ti O3.'.
- In case isotope is needed, specify something like this, 'Sr Ti1 (16O)3'.
- Only the stoichiometry number of '1' can be omitted.
To guarantee a successful calculation for neutron resonance, the mass density and radius inputs are required.
Mass density can either be directly specified or it can be calculated given mass and geometry inputs. The latter will win if both are specified.
Full number density and among other information is needed for packing fraction calculation.
The resonance can also be presented in Q-space, given that a series of scattering angles are provided.
