CamCASP/Programming/7

CamCASP => Programming => Propagator

Benzene

• Basis: Sadlej
• Old timings obtained using different processor (AMD), so using pyridine/sadlej timings (note: smaller basis set!):
  • DALTON: Kernel integrals: 3.3 hours
  • CamCASP: (properties) 2.5 hours
• New timings (ALDAX kernel):
  • Kernel: 6.5 minutes
  • CamCASP (only total polarizabilities): 12 minutes

Not quite a good comparison, but you get the idea. The new propagator is very very fast.

Accuracy is poor. ALDA(X) is just not good enough for <math>\pi</math>-conjugated systems. Here are the dipole-dipole polarizabilities:

ALDA+CHF kernel:

    43.247483     0.000000     0.000000
     0.000000    80.710408     0.000000
     0.000000     0.000000    80.713103
    Isotropic polarizability:    68.22366473
  Anisotropic polarizability:    37.46427266

ALDAX kernel:

 Order:    1 by    1
    39.035569     0.000000     0.000000
     0.000000    70.478442     0.000000
     0.000000     0.000000    70.487565
    Isotropic polarizability:    60.00052553
  Anisotropic polarizability:    31.44743535

That's a 12% error.