# 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Warning: this page is outdated.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¶

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