[CPMD-list] Getting lattice constant of Pt bulk

[Axel Kohlmeyer]

On Wed, 30 Mar 2005, Hong Won Keon wrote:

HK> Hi, CPMD-lists,

hi hong,

HK> I'm in trouble with getting lattice constant of Pt bulk.
HK> 
HK> I've tried many ways to do so, but still struggling.
HK> 
HK> I chose 3 PP - Goedecker PP, US PW91 PP which are available in CPMD and
HK> website and TM PW91 which I generate using fhi98PP.
HK> 

HK> To get equilibrium lattice constant, I did first, run "single point
HK> calculation - Wavefunction Optimization" then do "murnaghan fitting"
HK> with murn.x that was downloaded in fhi website. However, I cannot get
HK> good lattice constant which should be close to 3.92~4.0 A. 
HK> 
HK> Some say my calculation may be wrong. So I attach my input files for
HK> each PPs. Please give me some advice.

you won't get good results with gamma-point only calculations.
my guess is, that you need at least a 4x4x4 k-point mesh for 
anything useful.

please note, that the (current) cpmd code does not support
k-points with USPPs.


regards,
	axel.

HK>  
HK> 
HK> For TM PW91, I'm struggling to find out good PPs. To find out good PP, I
HK> check the PP with lattice constant. But still too far.
HK> 
HK>  
HK> 
HK>  
HK> 
HK> Please help me!
HK> 
HK>  
HK> 
HK> Thanks,
HK> 
HK>  
HK> 
HK> Hong won keon 
HK> 
HK>   
HK> 
HK> 

-- 

=======================================================================
Dr. Axel Kohlmeyer   e-mail: axel.kohlmeyer at theochem.ruhr-uni-bochum.de
Lehrstuhl fuer Theoretische Chemie          Phone: ++49 (0)234/32-26673
Ruhr-Universitaet Bochum - NC 03/53         Fax:   ++49 (0)234/32-14045
D-44780 Bochum  http://www.theochem.ruhr-uni-bochum.de/~axel.kohlmeyer/
=======================================================================
If you make something idiot-proof, the universe creates a better idiot.