## How do you calculate work function in DFT?

The work function in DFT is estimated as the difference between V(∞), the value of the electronic potential in the vacuum, and the Fermi level EF, which is the energy of the highest lying electron, which is the easiest to extract.

**What is SCF calculation in quantum espresso?**

0.1 Single-point (fixed-ion) SCF calculation. Set calculation=’scf’ (this is actually the default). Namelists &IONS and &CELL will be ignored. For LSDA spin-polarized calculations (that is: with a fixed quantization axis for magnetization), set nspin=2.

**How do you use the electric field in quantum espresso?**

The unit of an electric field is an atomic unit in Quantum Espresso. 1 V/Å is 0.0194469054 a.u.; hence, we need to put a value as a multiple of the value to set the magnitude of the electric field as V/Å unit. For example, 0.5 V/Å is 0.5 × 0.0194469054 = 0.0097234527.

### What is SCF and Nscf calculation?

NSCF stands for non-self-consistent field calculation and, as explicit by its name, the calculation is not performed in a self-consistent fashion as the SCF (self-consistent field) one.

**What is difference between relax and VC relax Quantum Espresso?**

‘vc’ stands for ‘variable cell’, so the cell shape (angles and length) as well as the atomic coordinates are optimized. Both the forces and stress tensor are calculated in ‘vc-relax’. ‘relax’ only does the atomic coordinates optimization, i.e., only the forces are calculated.

**What is the difference between Quantum ESPRESSO and VASP?**

VASP is a commercial code and Quantum-Espresso (QE) is an open source code.

## What is the difference between relax and VC relax?

**How do I download Quantum Espresso?**

Open the [Program Path] tab of the Preference Panel, click the […] button of [Quantum ESPRESSO]. Register the pw.exe file in the bin folder of the Quantum ESPRESSO installation folder, and click [OK]. ※ By default,”C:¥Program Files¥Quantum ESPRESSO 64-bit 5.2.