B3lyp games

Skip to content. Nowadays, reproducing results from a paper is extremely difficult: There are too many methods, too many software with different implementations. Computational details are poorly described, sometimes they are hidden by the authors.

Like this: Like Loading Leave a Reply Cancel reply Enter your comment here Fill in your details below or click an icon to log in:. Email Address never made public. Follow Following. Sign me up. Already have a WordPress. Log in now. Loading Comments So no calculations should go wrong.

As to what you identified as a typo in Molpro -- It may be that B88 was shoe-horned into the more mainstream definition of GGAs, which can be loosely worded as "a multiplicative correction to the LDA energy" the energy density, actually. NWChem makes the distinction explicit in the keyword nonlocal , see the manual section on exchange-correlation potentials. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group.

Create a free Team What is Teams? Learn more. Asked 6 years, 2 months ago. Active 8 months ago. Viewed 2k times. Improve this question. I will file a bug report for them to fix the wording. Since there are five formulae with two possible parameterizations mentioned in the VWN paper about local correlation, other programs may use other choices, and therefore generate different B3LYP energies. What are the differences between various software packages' default implementation of B3LYP and their capabilities, i.

Aesin already answered part of your question. Of course, choosing the same functional in both programs is not the only requirement to get identical results.

Some other things to consider are:. Basis set. Both programs have to use the exact same basis set. If you're using an internally stored basis set in Gaussian like, for example, G d,p , you can make Gaussian print the basis set details by adding the keyword GFINPUT to the route section.

Grid size. In Gaussian, the grid size can be controlled by the INT keyword. Integral cutoff. Both programs neglect very small integrals, as this will speed up the calculation without having a significant impact on accuracy. However, the cutoff factors between the two programs can be different, which can lead to slightly different results. SCF convergence. Both methods should converge towards the same solution, provided that your case is not too complex for DFT.

However, you should specify very tight convergence criteria if you'd like to compare energies obtained with both programs. Making both programs optimize to the exact same geometry is difficult, maybe even impossible. There might be other minor differences you've got to take into account.

Maybe it is best to start with a Hartree-Fock calculation, and see if the two programs yield the same SCF energy -- this takes differences in functional and DFT grid out of the equation.