[Pw_forum] Lattice Constant Optimization of Aluminum

[Paolo Giannozzi]

On Apr 26, 2007, at 5:41 , Paul M. Grant wrote:
> Even with a wildly wrong first estimate of celldm(1) of 7.2 (the  
> experimental value at RT is 7.665 au), I get zero net individual  
> atomic forces and thus no optimization.
"optimization wrt internal positions" != "optimization of the lattice  
parameter(s)".
Forces allow the former, stresses the latter. The simplest way to  
optimize the
lattice parameter of a simple crystal is to fit a few E(V) points to  
an equation
of state, using for instance "ev.f90"

Paolo
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Paolo Giannozzi, Democritos and University of Udine, Italy