$PCMGRD.                                                                        
                                                                                
--- The first two arrays control the density of tesserae                        
and the method to generate the tesserae.                                        
                                                                                
INITS  =  array defines the initial number of tesserae for                      
          each sphere. Only 60, 240 and 960 are allowed,                        
          but the value can be different for each sphere.                       
          (Default is INITS(1)=60,60,60,...)  See NTSALL.                       
                                                                                
METHOD =  array defining the tessellation method for each                       
          sphere.  The value can be different for each                          
          sphere.  The default is 4 for all spheres, e.g.                       
          METHOD(1)=4,4,4,...  See also MTHALL.                                 
       =  1  GEPOL-GB, "Gauss-Bonet" tessellation.                              
       =  2  GEPOL-AS, "area scaling" tessellation.                             
       =  3  GEPOL-RT, "regular tessellation".                                  
       =  4  FIXPVA, "Fixed points with variable area".                         
FIXPVA gives smooth potential surfaces during geometry                          
optimizations, works with $PCM options ICAV and IDISP (but                      
not with IDP or IRP), and is the preferred tessellation                         
method.                                                                         
                                                                                
--- The next three parameters are presets for filling the                       
    arrays INITS and METHOD with identical values.                              
                                                                                
NTSALL =  60, 240 or 960 (default = 60)                                         
          All values in the array INITS are set to NTSALL                       
                                                                                
MTHALL =  1, 2, 3, or 4 (default = 4)                                           
          All values in the array METHOD are set to MTHALL                      
                                                                                
MTHAUT =  0 or 1 (default = 0)                                                  
          If RUNTYP=OPTIMIZE and frozen atoms are defined                       
          by IFCART, MTHAUT=1 will select METHOD=1 for                          
          frozen atoms. See also AUTFRE and NTSFRZ.                             
                                                                                
note: Explicitly defining INITS and METHOD from the input                       
      deck will overrule the presets from NTSALL, MTHALL                        
      and/or MTHAUT.                                                            
                                                                                
--- The following two parameters control GEPOL-RT                               
                                                                                
AREATL =  The area criterion (A*A) for GEPOL-RT.                                
          Tesserae with areas < AREATL at the boundary of                       
          intersecting spheres will be neglected.                               
          Default=0.010 A*A. Smaller AREATL cause larger                        
          number of tesserae.  AREATL < 0.00010 is not                          
          recommended.                                                          
                                                                                
BONDRY =  Controls (by scaling) the distance within which                       
          tesserae are considered "close" to the boundary.                      
          Such tesserae will be recursively divided into                        
          smaller ones until their areas are < AREATL.                          
          The default (= 1.0) means the distance is the                         
          square root of the tessera area.                                      
          A large BONDRY value like 1000.0 will lead to                         
          fine tessellation for the entire surface with                         
          all tessera areas < AREATL.                                           
                                                                                
--- The next two parameters are only relevant if MTHAUT=1                       
                                                                                
AUTFRE =  Distance (A) for frozen atoms to be treated as                        
          moving atoms when MTHAUT=1. Default=2.0 A.                            
                                                                                
NTSFRZ =  60, 240 OR 960, initial tessera number for                            
          frozen atoms. Default=60                                              
                                                                                
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generated on 7/7/2017