## What kind of functional is PBE?

exchange-correlation functional

PBE (Perdew et al., 1996) is the default exchange-correlation functional. It is recommended, especially, for studies of molecules interacting with metal surfaces, although it is also fairly reliable for bulk calculations.

## What is PBE0?

PBE0 is a hybrid functional (different class than GGA) which is based on PBE. Hybrid functionals include an additional term representing the HF exchange, not present in GGA functionals.

**What is Gaussian distribution law?**

Normal distribution, also known as the Gaussian distribution, is a probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean. In graph form, normal distribution will appear as a bell curve.

**What is the Gaussian distribution?**

The Gaussian distribution, so named because it was first discovered by Carl Friedrich Gauss, is widely used in probability and statistics.

### What is the difference between pbe0 and GGA?

PBE0 is a hybrid functional (different class than GGA) which is based on PBE. Hybrid functionals include an additional term representing the HF exchange, not present in GGA functionals. There is no way to answer your question easily, because everything depends on the system, model etc.

### What is the spacing between the pixels in a Gaussian distribution?

The spacing between each sampling (i.e. the distance between pixels measuring the data) is uniform. The peak is “well-sampled”, so that less than 10% of the area or volume under the peak (area if a 1D Gaussian, volume if a 2D Gaussian) lies outside the measurement region.

**Which functionals in Gaussian 16 include the gd3bj model?**

The table below gives the list of functionals in Gaussian 16 for which GD3BJ parameters are defined. The functionals highlighted in bold include this dispersion model by default when the indicated keyword is specified (e.g., B2PLYPD3 ). For the rest of the functionals, dispersion is requested with EmpiricalDispersion=GD3BJ.