non-orthorhomic variable cell optimization
monica
monic... at phys.chem.ethz.ch
Fri Feb 13 14:33:34 UTC 2009
Dear Rad,
I was running recently several triclinic cell optimization jobs
(although the angles are very close to 90), with variable hydrostatic
pressure (0-20 GPa), and it seemed to work: when comparing the volume
with similar orthorhombic cell, optimized manually (energy volume
curve). See output below for example. In my case, when the cell was
already close to the minimum, only minor changes occurred.
Monica
output for example
CELL| Volume
[ANGSTROM**3]: 1798.737
CELL| Vector a [ANGSTROM]: 9.814 0.000 0.000 |a|
= 9.814
CELL| Vector b [ANGSTROM]: 0.424 9.038 0.000 |b|
= 9.048
CELL| Vector c [ANGSTROM]: 1.575 0.001 20.279 |c|
= 20.340
CELL| Angle (b,c)
[degree]: 89.790
CELL| Angle (a,c)
[degree]: 85.559
CELL| Angle (a,b)
[degree]: 87.314
CELL| Grid size for subcell
generation 2.000
CELL| Volume
[ANGSTROM**3]: 1795.645
CELL| Vector a [ANGSTROM]: 9.807 0.000 0.000 |a|
= 9.807
CELL| Vector b [ANGSTROM]: 0.424 9.031 0.000 |b|
= 9.041
CELL| Vector c [ANGSTROM]: 1.575 -0.001 20.276 |c|
= 20.337
CELL| Angle (b,c)
[degree]: 89.795
CELL| Angle (a,c)
[degree]: 85.559
CELL| Angle (a,b)
[degree]: 87.312
CELL| Grid size for subcell
generation 2.000
CELL| Volume
[ANGSTROM**3]: 1785.878
CELL| Vector a [ANGSTROM]: 9.783 0.000 0.000 |a|
= 9.783
CELL| Vector b [ANGSTROM]: 0.424 9.008 0.000 |b|
= 9.018
CELL| Vector c [ANGSTROM]: 1.574 -0.006 20.266 |c|
= 20.327
CELL| Angle (b,c)
[degree]: 89.810
CELL| Angle (a,c)
[degree]: 85.560
CELL| Angle (a,b)
[degree]: 87.307
On Feb 11, 10:47 pm, Rad <rad.... at arl.army.mil> wrote:
> Hello everybody,
>
> We seem to be having an issue with non-orthorhombic cell optimization
> when the lattice has all the three angles other than 90 degrees. Here
> is what appears to be happening: After the initial set up, the module
> Changes the lattice vectors by keeping the lengths the same but the
> angles are slightly different. This happens only when all the angles
> are not 90-degrees. The regtest for non-orthorhombic includes only one
> angle 120 and the rest are 90s. So the scenario I described might be
> missed out. This issue we have observed in several executables we have
> built over the last several months and on multiple architectures.
>
> ==================================================================================
> Here is the output just after the set up which is the same as the
> input:
> CELL| Volume
> [ANGSTROM**3]: 442.524
> CELL| Vector a [ANGSTROM]: 9.010 0.000 0.000 |a|
> = 9.010
> CELL| Vector b [ANGSTROM]: -4.510 7.821 0.000 |b|
> = 9.028
> CELL| Vector c [ANGSTROM]: -0.216 -2.630 6.280 |c|
> = 6.812
> CELL| Angle (b,c)
> [degree]: 108.580
> CELL| Angle (a,c)
> [degree]: 91.820
> CELL| Angle (a,b)
> [degree]: 119.970
>
> Here is when it got changed just before the first step of the
> optimization:
>
> CELL| Volume
> [ANGSTROM**3]: 449.960
> CELL| Vector a [ANGSTROM]: 9.010 0.000 0.000 |a|
> = 9.010
> CELL| Vector b [ANGSTROM]: -4.510 7.821 0.000 |b|
> = 9.028
> CELL| Vector c [ANGSTROM]: -0.216 -2.363 6.386 |c|
> = 6.812
> CELL| Angle (b,c)
> [degree]: 106.534
> CELL| Angle (a,c)
> [degree]: 91.820
> CELL| Angle (a,b)
> [degree]: 119.970
> CELL| Grid size for subcell
> generation 2.000
>
> -------- Informations at step = 0 ------------
> Optimization Method = SD
> Total Energy = -386.4717739715
> Internal Pressure [bar] = 18296.7247113471
> ---------------------------------------------------
>
> --------------------------
> OPTIMIZATION STEP: 1
> =================================================================================
> Could someone please take a look at this issue and let me know what
> might be the issue.
>
> Thanks
> Rad
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