## What is Pbepbe?

The designation PBEPBE is an actual terrible artefact from researchers using Gaussian. The actual publication[1, 2] only refers to it as PBE, and most other program packages (I know) implement it as such. Often they make the correlation and exchange parts separately available via PBEC and PBEX, or similar.

### What is B3LYP Gaussian?

B3LYP uses the non-local correlation provided by the LYP expression, and VWN functional III for local correlation (not functional V). Note that since LYP includes both local and non-local terms, the correlation functional used is actually: C*ECLYP+(1-C)*ECVWN.

#### What is a functional in Gaussian?

In mathematics, a Gaussian function, often simply referred to as a Gaussian, is a function of the form. for arbitrary real constants a, b and non-zero c. It is named after the mathematician Carl Friedrich Gauss. The graph of a Gaussian is a characteristic symmetric “bell curve” shape.

**How do you calculate DFT in Gaussian?**

First of all, you should build your molecule or compound using Gaussian View 6 and you can build a simple one for test, then go to Gaussian program and choose the ” Gaussian calculation setup” from calculation menu then you can choose from “job type” energy, optimization,.. then from “Method” you can choose HF method.

**What is the difference between PBE and PBEsol?**

A simple modification of PBE is the PBEsol functional, which differs from PBE only in two parameters, and is designed to improve upon PBE for equilibrium properties of bulk solids and their surfaces. The main difference between them is that they are based upon different selections of exact constraints to satisfy.

## What is DFT Modelling?

Density-functional theory (DFT) is a computational quantum mechanical modelling method used in physics, chemistry and materials science to investigate the electronic structure (or nuclear structure) (principally the ground state) of many-body systems, in particular atoms, molecules, and the condensed phases.

### What Gaussian 16?

Gaussian 16 is the latest version of the Gaussian series of electronic structure programs, used by chemists, chemical engineers, biochemists, physicists and other scientists worldwide. Gaussian 16 provides a wide-ranging suite of the most advanced modeling capabilities available.

#### What is DFT D3?

Based on a molecular geometry as the only input, DFT-D3 provides corrections to the molecular total energy, energy gradient and frequencies that are added to the results obtained with nearly any conventional density-functional theory approximation and also some other common mean-field approaches.

**What Gaussian 09?**

What is gaussian09? Gaussian is a computer program used by chemists, chemical engineers, biochemists, physicists and other scientists. It utilizes fundamental laws of quantum mechanics to predict energies, molecular structures, spectroscopic data (NMR, IR, UV, etc) and much more advanced calculations.

**What is PBEsol functional?**

[1] presents a new functional, PBEsol, intended for solid state and surface systems. It is based on a gradient expansion of the ex- change energy and a final fit of the exchange-correlation (xc) energy to that of surface jellium.

## What is GGA PBE?

Generalized gradient approximations (GGA) of Perdew- Burke- Ernzerhof (PBE) have been adopted for exchange-correlation potential. Calculated electronic band structure reveals the metallic character of the compound.

### Is DFT semi empirical?

It is true when you are lucky. However, DFT and semi-empirical methods are all semi-empirical. For hybrid functional, parameters are got from fitting data bases, too. If your system is very similar with some published work, it can be a good choice to use that functional.