[CPMD-list] problems using correlation functional

Massimiliano Tirone tironem at fiu.edu
Thu Aug 14 21:59:25 CEST 2003


Hi,
I am experiencing problems using correlation functional.
When I create and input file with something like:
&DFT
 FUNCTIONAL LDA
 LDA CORRELATION PZ
&END
I have a crash with an ** Address Error **

If I remove  LDA CORRELATION PZ, using just:
&DFT
 FUNCTIONAL LDA
&END
the run is ok but in the output file there is something like:
    LDA EXCHANGE:                                            NONE
    LDA XC THROUGH PADE APPROXIMATION
    S.GOEDECKER, J.HUTTER, M.TETER PRB 54 1703 (1996)

My patch for this is to replace  FUNCTIONAL LDA with:
&DFT
 SLATER
 0.6666666
 LDA FUNCTIONAL NO
&END
and in the output I get:
 EXCHANGE CORRELATION FUNCTIONALS       
    LDA EXCHANGE:                        SLATER (ALPHA = 0.66667)
    LDA CORRELATION:                                         NONE

now, the only way I can have exchange and correlation functionals
is to use in the input file:
 &DFT
 SLATER
 0.66666666
 LDA CORRELATION PZ
 EXCHANGE CORRELATION TABLE NO
 &END
and in the output file everything seems fine:
 EXCHANGE CORRELATION FUNCTIONALS
    LDA EXCHANGE:                        SLATER (ALPHA = 0.66667)
    LDA CORRELATION:                              PERDEW & ZUNGER
       [J.P. PERDEW AND A ZUNGER, PRB 23 5048 (1981)]


Does this make any sense?
Last piece of information, this is independent from: type of atoms, 
type of correlation functionals, type of system (crystal or molecule)
and type of PP (KB or Goedecker but I havent tried Vanderbilt PP).
CPMD (3.7.1) is compiled with IFC and is running on a P4 machine.


Max
ps. hope this is not too confusing.




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