$RDF group                     (relevant for RUNTYP=MD)                         
  This group defines the pairs of atoms for which the                           
radial distribution functions are to be computed, at the                        
end of a molecular dynamics trajectory.  The input is                           
similar in style to $EFRAG, consisting of separate lines,                       
with the word STOP ending each particular pair.                                 
Line 1.   NRDF=                                                        
gives the number of RDFs which should be computed.                              
Line 2.                                     
gives a string for the printout (a good choice involves                         
both atoms, such as ClCl), the name of the $FRAGNAME                            
containing the first atom of the pair, the name of the                          
$FRAGNAME input group with the second atom of the pair, and                     
how many such pairs exist.                                                      
Line 3.   

generated on 7/7/2017