[Wien] Alkali hydrides elastics constants

[Nenad Ivanovic]

Hello everybody

I am calculating Alk-H series.

The problem we have is connected to calculation of elastic constants.
Everything went fine with Li, Na and K cases, but We cannot obtain
meaningful results for CsH and RbH.

For CsH eos and tetra results look OK, but rhomb energy variations are
very small, tipically on 4th decimal place, it looks like system is not
sensible enough on this type of distorsion. Good results for eos and
tetra cases emerged only after increasing Gmax factor to 20.

Situation is far worse for RbH with large fluctuations for tetra and
again weak sensibility for rhomb case.

We already did elastic constants (only C11 and C12) for same systems few
years ago by hand with WIEN97 and everything went fine (sensible results 
comparable with previous findings).
Perhaps it has something to do with APW+lo basis set???

Details of calculations:

Complete apw+lo basis set.

RbH: RMT 2.2 a.u for Rb and 1.6 a.u for H (large interatomic distance
throughout whole series)
CsH: RMT 2.3 a.u. for Cs and 1.6 a.u. for H

RmtKmax 8
GGA96, with -7 ryd separation energy
4000 k-points in whole unit cell for all configurations
Gmax 20

The other question is regarding compiled binaries on our system. LAPW1
crashes with SIGSEGV whenever we try to calculate system with more then
few atom per unit cell (includeing test case of course). This does not
happen if we use supplied precompiled binaries.

I read article by Gerhard H. Fecher about compiling
Wien2k on Intel systems where he described similar problem with
calculation of more complicated systems, due to combination of
statically linked binaries and some GNU libraries. We have tried both
statically and dynamically liking with same result. Does anyone knows
the origin of this problem?

BTW, with latest update of wien2K, calculations crash in first cycle in 
lapw2 with infamous 'error in LAPW2' message description (same compiler 
options as for previous version of wien).

Operating system is Slackware 10.1 kernel 2.6.18.2

Hardware: dual core 2 E6400 on 2.17 GHz with 1GB RAM.

Compiler ifc 9.1 + mkl 8.1.
current compiler options:
FOPT =  -FR -mp1 -w -prec_div -pad -ip -DINTEL_VML -O3 -xT -axT -openmp
FPOPT = -FR -mp1 -w -prec_div -pc80 -pad -ip -DINTEL_VML
LDFLAGS = -L/opt/intel/mkl/8.1/lib/32 -i-static -lguide -lguide_stats 
-lsvml -lpthread
R_LIBS = -L/opt/intel/mkl/8.1/lib/32 -lmkl_lapack -lmkl_ia32
C_LIBS = $(R_LIBS)

Best regards

Nenad Ivanovic







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