On data cards, every particle name (1 ... 12 characters) has to be terminated by exactly one blank space.
Example
PMOD 'PI+ PI- ' 0.14 ! is correct !
PMOD 'PI+ PI-' 0.14 ! SERIOUS MISTAKE !
In the Fortran program, this extra blank space can be omitted or typed.
Lower case characters are translated into upper case characters. It would be wise, nevertheless, to use UPPER case characters only.