The ABINIT Users Mailing List ( CLOSED )

[dylu@ucdavis.edu]

Hello, dear abinit developers:
       I have a few questions regarding the wavelets implementation in 
Abinit5.2 through "icoultrtmt" and "nscforder". After reading the release 
notes and the BigDFT webpage, though not much information available, I 
figured that it might be good for calculations of non-periodic systems, since 
the Hartree and PSP local terms  are evalulated through Poisson solver using 
open boundary conditions. 
      
1. As for the example, v5_t07, why the K-point is shifted to 0.5 0.5 0.5 but 
not on the Gama point, which seems to me a natural choice for cluster 
calculations?

2. I expect the new method has a much better convergence regarding Etotal and 
EHartree, if I understand it correct, since there is no image Coulomb 
interaction. I modified the super cell size as the following in t07.in:

ndtset 5
acell: 3*5
acell+ 3*2.5

After a standard plane wave calculation using Abinit5.1.2, I got reasonable 
numbers:
[deyulu@zinfandel test512]$ grep Etotal *out
    >>>>>>>>> Etotal= -3.24266940241069E-01
    >>>>>>>>> Etotal= -4.26599328552894E-01
    >>>>>>>>> Etotal= -4.42120273713403E-01
    >>>>>>>>> Etotal= -4.44678592202608E-01
    >>>>>>>>> Etotal= -4.45102876652833E-01
[deyulu@zinfandel test512]$ grep "Hartree energy " *out
    Hartree energy  =  1.32705836887717E-01
    Hartree energy  =  1.38492352304226E-01
    Hartree energy  =  1.56214176716576E-01
    Hartree energy  =  1.74895165654710E-01
    Hartree energy  =  1.90593035878911E-01

Playing with the wavelets, the results seem to be very unstable. 
Can someone provide more information about this implementation and
tell me what is going wrong?

nscforder  8     # Order of scaling used by kernel
!nscforder2 14
!nscforder3 16
!nscforder4 20
!nscforder5 24

[deyulu@zinfandel tmp]$ grep Etotal *out
    >>>>>>>>> Etotal= -3.24272603801180E-01
    >>>>>>>>> Etotal= -1.00569442580796E+00
    >>>>>>>>> Etotal= -1.69531799128392E+00
    >>>>>>>>> Etotal= -2.37427341162027E+00
    >>>>>>>>> Etotal= -2.97559451789859E+00


[deyulu@zinfandel tmp]$ grep "Hartree energy " *out
    Hartree energy  =  3.89261939710595E-01
    Hartree energy  =  4.31111370942495E-01
    Hartree energy  =  5.26095331415071E-01
    Hartree energy  =  5.72879491830780E-01
    Hartree energy  =  5.85224698919510E-01

Thanks
Deyu Lu