$TESCAV group                              (optional)                           
    This group controls the tessellation procedure for the                      
cavity surfaces in PCM computations.  The default values                        
for this group will normally be satisfactory.  Use of the                       
FIXPVA mechanism for dividing the surface of the atomic                         
spheres into tesserae should allow for convergent PCM                           
geometry optimizations.  To converge to small OPTTOL values                     
may require the use of internal coordinates, since the                          
tessellation amounts to a finite grid (so the PCM energy is                     
not strictly rotationally invariant).                                           
   Cartesian geometry optimizations may require a high                          
density of tesserae on the cavity surface:                                      
    NTSALL=240   (or 960)                                                       
This may require raising the maximum number of tesserae,                        
see MXTS in $PCM.  It is reasonable to just try internal                        
coordinates first, as this should be sufficient w/o                             
increasing the tesserae density.  See also IFAST=1 in                           
--- 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                         
--- 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                          
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                                              

generated on 7/7/2017