Thank you Azadeh Kordzadeh but i already have .cif and .pdb format files. I want to convert then into .wfn or .fch or .molden formats.

Simple file conversion tools will not work since to generate either .wfn and .chk one needs to at least perform single-point calculations with those molecular coordinates. I think it will be much better if you can collaborate with someone who has access to Gaussian code.

Thank you very much Turbasu Sengupta. If somebody is interested in such collaboration, please, feel free to contact me?

Turbasu Sengupta I have a similar query, I want to calculate the ESP maxima and minima using M062X 631++G(dp) level of theory, I need .wfn file for to use in multiwfn, is there any way to obtain it at much lower computational cost and time? The molecule I am working on have 69 atoms and I am using ORCA which takes a lot of time.

Hello Arun,

If you have a limited facility, you can try to reduce the DFT functional and basis set and see how the results come out. Reducing the level of theory might impact the accuracy of the result, so better check before finalizing the results.

Turbasu Sengupta Thank you for the answer, I have already checked that and yes there is a difference in the results that is why I wanted to know if there is an alternative where I can skip the geometry optimization part and just get a wfn file. I am new and still learning computational chemistry so please excuse me for the ignorance.

As Arun Kumar, I an new in computational chemistry. The molecule I am working on have 26 atoms. Is geometry optimization output file embeded information like single-point calculations ?

Koffi Sénam Etse I am also new to this field and still learning so I am really sorry I do not have an idea about it.

You can convert cif file to wfn file by opening cif file using gaussview the performing any job for gaussian with keyword "out=wfn".

Dear Koffi Sénam Etse ,

In principle, you could use one of ORCA its low-cost methods: HF-3c, PBEh-3c or B97-3c. Please take a look at the manual (and also on the papers of those methodologies) to check if they are adequate for your purposes/molecules. But in general, they yield good geometries. Resulting .gbw files (containing the wavefunction) can be converted to .molden or .wfn files using orca_2mkl or orca_2aim, respectively.

You can also use XTB, another low-cost software/methodology that can perform geometry optimization and delivers wavefuntions in .molden format. This one will be really fast for a 26 atoms system (https://github.com/grimme-lab/xtb).

Best,

Felippe