Comet parameter: use_C_ions
         
         - Controls whether or not C-ions are considered in the search.
         
- Valid values are 0 and 1.
         
- To not use C-ions, set the value to 0.
         
- To use C-ions, set the value to 1.
         
- The default value is "0" if this parameter is missing.
         
Example:
         
use_C_ions = 0
         
use_C_ions = 1