RI-J calculations

For non-hybrid functionals we strongly recommend the RI-$J$ mathend000# procedure, which speeds up calculations by a factor 10 at least (as compared to conventional treatments) without sacrificing accuracy. Command ri gives:

STATUS OF RI-OPTIONS:
    RI IS NOT USED
    Memory for RI:           200 MB
    Filename for auxbasis: auxbasis

 ENTER RI-OPTION TO BE MODIFIED
      m: CHANGE MEMORY FOR RI
      f: CHANGE FILENAME
   jbas: ASSIGN AUXILIARY RI-J BASIS SETS
     on: TO SWITCH ON  RI
 Use <ENTER>, q, end, or * to leave this menu

Activate RI-$J$ mathend000# with on, and choose with m the memory you can dedicate to store three-center integrals (Keyword: $ricore), default is 200MB. The more memory, the faster the calculation.

A rough guide: put $ricore to about $2/3$ mathend000# of the memory of the computer. Use OS specific commands (top on most UNIX systems), during an RIDFT run to find the actual memory usage and then adjust $ricore, the keyword in control specifying memory.

If the option jbas is selected, DEFINE enters a submenu which allows the assignment of auxiliary basis sets (for an explanation of the menu items see Section 4.2). Where available, the program will select by default the auxiliary basis sets optimized for the orbital basis used. Please note that treatment of systems with diffuse wavefunctions may also require an extension of the auxiliary basis. For this cases enlarge the sets of s- and p-functions with diffuse functions.

The RI-$J$ mathend000# option is only supported by programs RIDFT and RDGRAD, if you use JOBEX to optimize molecular geometry, put: nohup jobex -ri ...