General Atomic and Molecular Electronic Structure System (GAMESS)

https://www.msg.chem.iastate.edu/index.html

and

Gaussian

https://gaussian.com/

GAMESS is open access while Gasussian required a licence.

Gaussian 09 but you required a licence.

For solid state, VASP is also very popular:

https://www.vasp.at/

It is admittedly a too far open question. You need to be a bit more specific on what you want to do. Assuming you want to do static calculations:

1) For solids, usually select a plane wave code since it will leverage on the periodicity of the lattice

2) For molecules/clusters/isolated systems, select a localised basis set or real space since you will only calculate what you need.

If you go for 1, VASP, Quantum Espresso, ABINIT are good tools - very well developed and advanced. If you need super large systems, have a look at CASTEP/ONETEP or DFT-B.

If you go for 2, then Gaussian09, ORCA, NWCHEM, GAMESS, Octopus are possibly the tools to choose.

Keep in mind that some are free to use, others (VASP, Gaussian) require a licence (expensive).

All codes have a quite developed user base so you might find somebody helping in case of errors.

Finally, if you need more advanced methods (GW, transport calculations) then you might focus first on that code and then select one of the standard DFT suites that better interfaces with the first. It is bad if you discover that you did some calculations and then you cannot use those results.

ORCA can also be used.

Hello, that would depend on your ambitions.

Here is a good overview over software capabilities: https://en.wikipedia.org/wiki/List_of_quantum_chemistry_and_solid-state_physics_software

On the other hand, I'd assume you are more like a lonesome researcher (hence your question). I'd like to suggest to check for software with a broad user community. Support is much easier this way.

Greetings. It depends on the property you want to calculate and the computing power you have. I use WIEN2k_2018 for its versatility and easy access to routines for different properties. Its authors have taken care to provide a user-friendly and easy-to-use manual.

ORCA and for better accuracy Gaussian16

Safa Ben Amara it should be clear that all codes can in principle reach the same level of accuracy for the system they have been built for -- Accuracy comes primarily from the convergence of the physical parameters and the choice of pseudo potentials suited for your calculations. Doing solid structures with Gaussian or ORCA might be more computationally demanding than with VASP or Quantum Espresso (to name two), but at convergence all codes should give you the same results (assuming you are using the same level of theory). This is ultimately the reason why not everybody is using Gaussian or VASP...

I have been able to solve my problem with the suggestions given. Thank you all for your contributions.