The ABINIT Users Mailing List ( CLOSED )

["Wu Rongqin" <g0203654@nus.edu.sg>]

Dear Wang,

    When you choose the exchange-correlation functional, you should first 
look at the pspxc value  in the pseudopotential files. So just use the same 
value as pspxc for ixc and the warning message will disappear. Actually, the 
result has something to do with your exchange-correlation function and this 
is a common sense. Please see the description of ixc.

    Cheer up

    Rongqin Wu 

-----Original Message-----
From: zeng zhenhua [mailto:myid520@hotmail.com] 
Sent: 2004年3月29日 22:59
To: forum@abinit.org
Subject: [abinit-forum] Cohesive energy of hydrogen with metals

dear all:
    I'm calculate the cohesive energy of hydrogen with metals.In the 
calculation I come across tow problem.The first One is a warning accuring 
which is same as the happened in the first lesson  of tutorial:
------------------------------------------------------------------------
pspatm: WARNING -
  Pseudopotential file pspxc=       7,
  not equal to input ixc=       1.
  These parameters must agree to get the same xc
  in ABINIT code as in psp construction.
  Action : check psp design or input file.
  Assume experienced user. Execution will continue.
------------------------------------------------------------------------
I want to know whether it influences the result or not.
The second is I calculate the cohesive energy of hydrogen with metals 
through calcuating a series of total enery with diffrent acell and fit them 
.But I find the result is very lager than experimental data. For example 
the cohesive hydrygen with aluminum,the following is the input file,the 
calculating result is about 5ev,but the experiment result is only 3.25ev.
I hope someone could kindly help me.
Thanks!
Zhenhua Zeng
physics department, Hunu University, PRC,410082

#box Al-H
ndtset 15

ngkpt 4 4 4

ecut  15.0          
kptopt   1        

#Definition of the unit cell
acell: 3*4          
acell+ 3*1
                      

#Definition of the atom types
ntype 2                # There are two types of atom
znucl 1 13          
#Definition of the atoms

natom 2                # There are two atoms
type 1 2               # The first is of type 1 (H), the second is of type 
2 (Al).
xred                   # This keyword indicate that the location of the 
atoms
                       # will follow, one triplet of number for each atom
   0.0 0.0 0.0       # Triplet giving the REDUCED coordinate of atom 1.
   0.5 0.5 0.5       # Triplet giving the REDUCED coordinate of atom 2.

toldfe 1.0d-6

nstep 50               # Maximal number of SCF cycles

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