Molecule tests

Warning: this page is outdated. For performance of GPAW for molecular systems refer to G2-1 database.

Atomization energies and bond lengths for a set of small molecules have been calculated with the PBE functional. All calculations are done with a grid spacing of 0.16 Å, zero-boundary conditions and approximately 6 Å of vacuum surrounding the molecules. Compensation charges are expanded with correct multipole moments up to \(\ell_{max}=2\). Open-shell atoms are treated as non-spherical with integer occupation numbers, and zero-point energy is not included in the atomization energies. The numbers are compared to very accurate, state-of-the-art, PBE calculations 1. The script that does the calculations is molecule_test.py.

Bond lengths

../_images/bondlengths.png

Bondlengths in Å:

dimer

GPAW

reference

error

\(\rm{BeH}\ (\rm{beryllium}\ \rm{monohydride})\)

1.357

1.354

+0.003

\(\rm{ClO}\)

1.584

1.576

+0.008

\(\rm{CO}\)

1.141

1.136

+0.005

\(\rm{CN}\ (\rm{Cyano}\ \rm{radical})\)

1.172

1.173

-0.001

\(\rm{FCl}\)

1.652

1.648

+0.004

\(\rm{LiH}\)

1.611

1.604

+0.007

\(\rm{F}_2\)

1.414

1.414

+0.000

\(\rm{LiF}\)

1.607

1.583

+0.024

\(\rm{Na}_2\)

3.077

3.087

-0.010

\(\rm{CH}(\rm{Methylidyne})\)

1.135

1.136

-0.001

\(\rm{HCl}\)

1.289

1.287

+0.002

\(\rm{Li}_2\)

2.728

2.728

+0.000

\(\rm{N}_2\)

1.101

1.103

-0.002

\(\rm{O}_2\)

1.234

1.218

+0.016

\(\rm{Cl}_2\)

2.007

1.999

+0.008

Atomization energies

Atomization energies in eV:

molecule

GPAW

reference

error

\(\rm{BeH}\ (\rm{beryllium}\ \rm{monohydride})\)

2.399

2.407

-0.008

\(\rm{C}_2\rm{H}_2\)

18.046

17.974

+0.072

\(\rm{C}_2\rm{H}_4\)

24.837

24.761

+0.076

\(\rm{C}_2\rm{H}_6\)

31.129

31.049

+0.080

\(\rm{CH}(\rm{Methylidyne})\)

3.675

3.673

+0.002

\(\rm{CH}_2\ (^1\rm{A}_1)\)

7.767

7.754

+0.013

\(\rm{CH}_2\ (^3\rm{B}_1)\)

8.441

8.430

+0.011

\(\rm{CH}_3\)

13.458

13.430

+0.028

\(\rm{CH}_3\rm{Cl}\)

17.356

17.320

+0.036

\(\rm{H}_3\rm{COH}\)

22.552

22.519

+0.033

\(\rm{H}_3\rm{CSH}\)

20.745

20.719

+0.026

\(\rm{CH}_4\)

18.233

18.196

+0.037

\(\rm{CN}\ (\rm{Cyano}\ \rm{radical})\)

8.535

8.564

-0.029

\(\rm{CO}\)

11.617

11.648

-0.031

\(\rm{CO}_2\)

18.002

18.013

-0.011

\(\rm{SC}\)

7.790

7.784

+0.006

\(\rm{Cl}_2\)

2.841

2.853

-0.012

\(\rm{FCl}\)

3.134

3.135

-0.001

\(\rm{ClO}\)

3.515

3.539

-0.024

\(\rm{F}_2\)

2.312

2.281

+0.031

\(\rm{H}_2\rm{CO}\)

16.734

16.717

+0.017

\(\rm{H}_2\rm{O}\)

10.119

10.134

-0.015

\(\rm{HOOH}\)

12.204

12.211

-0.007

\(\rm{HCN}\)

14.190

14.150

+0.040

\(\rm{HCO}\)

12.790

12.788

+0.002

\(\rm{HCl}\)

4.606

4.610

-0.004

\(\rm{HF}\)

6.156

6.136

+0.020

\(\rm{HOCl}\ (\rm{hypochlorous}\ \rm{acid})\)

7.590

7.597

-0.007

\(\rm{Li}_2\)

0.865

0.863

+0.002

\(\rm{LiF}\)

5.981

6.002

-0.021

\(\rm{LiH}\)

2.331

2.320

+0.011

\(\rm{N}_2\)

10.572

10.568

+0.004

\(\rm{H}_2\rm{NNH}_2\)

19.713

19.631

+0.082

\(\rm{NH}\)

3.836

3.842

-0.006

\(\rm{NH}_2\)

8.186

8.183

+0.003

\(\rm{NH}_3\)

13.124

13.083

+0.041

\(\rm{NO}\)

7.417

7.459

-0.042

\(\rm{Na}_2\)

0.766

0.768

-0.002

\(\rm{NaCl}\)

4.101

4.059

+0.042

\(\rm{O}_2\)

6.158

6.214

-0.056

\(\rm{OH}\)

4.749

4.757

-0.008

\(\rm{P}_2\)

5.232

5.269

-0.037

\(\rm{PH}_2\ (\rm{Phosphino}\ \rm{radical})\)

6.674

6.700

-0.026

\(\rm{PH}_3\)

10.329

10.364

-0.035

\(\rm{S}_2\)

4.980

5.004

-0.024

\(\rm{SH}_2\)

7.875

7.892

-0.017

\(\rm{SO}\)

6.085

6.136

-0.051

\(\rm{SO}_2\)

12.057

12.190

-0.133

\(\rm{Si}_2\ (\rm{Silicon}\ \rm{diatomic})\)

3.507

3.526

-0.019

\(\rm{Si}_2\rm{H}_6\)

22.458

22.528

-0.070

\(\rm{SiH}_2\ (^1\rm{A}_1)(\rm{silicon}\ \rm{dihydride})\)

6.388

6.414

-0.026

\(\rm{SiH}_2\ (^3\rm{B}_1)(\rm{silicon}\ \rm{dihydride})\)

5.670

5.694

-0.024

\(\rm{SiH}_3\)

9.601

9.636

-0.035

\(\rm{SiH}_4\)

13.542

13.586

-0.044

\(\rm{SiO}\)

8.428

8.482

-0.054

References

1

“The Perdew-Burke-Ernzerhof exchange-correlation functional applied to the G2-1 test set using a plane-wave basis set”, J. Paier, R. Hirschl, M. Marsman and G. Kresse, J. Chem. Phys. 122, 234102 (2005)

[2] “Molecular and Solid State Tests of Density Functional

Approximations: LSD, GGAs, and Meta-GGAs”, S. Kurth, J. P. Perdew and P. Blaha, Int. J. Quant. Chem. 75, 889-909 (1999)

3

“Comment on ‘Generalized Gradient Approximation Made Simple’”, Y. Zhang and W. Yang, Phys. Rev. Lett.

[4] Reply to 3, J. P. Perdew, K. Burke and M. Ernzerhof