Multiwfn

Multiwfn is a program which can be used to modify and analyse calculated wave functions. Examples of what can be done with Multiwfn are AIM, NCI, ELF, and LOL calculations. Have a look at the documentation. It is very good, provides lots of examples and explains the theory behind what is going on in the program.

General

Multiwfn was written to work under Windows machines! Macs and Linux computers can be made to run Multiwfn but the program is quite unstable then.

Initial instructions

If you have a windows machine you are good to go. If not use one of the college computers. Wake one of the machines, press ctrl + alt + delete, and sign in with your college credentials. Download the most suitable software from http://sobereva.com/multiwfn/. Most of the machines you will use should be 64 bit systems these days. But to be sure check it, using the looking at the System of your computer.

Navigate into the Download directory and uncompress the downloaded file. The college machines come with 7zip. Right click on the compressed Multiwfn file, choose 7zip and use "unzip here". Drag and drop the uncompressed directory to a location of your choice (e.d. the Desktop)

Now you already finished setting up the program!

Example

Check which kind of input file is needed for the calculation you want to perform. Most of the calculations can be run easily with a formatted Gaussian check point file. In the next passage there will be a brief example of how to run an ELF calculation on caffeine.

So, use the forecheck utility of gaussian to

Generate the input:

If you are using the HPC, enter the following into the terminal

module load gaussian formchk caffeine.chk caffeine.fchk

Copy and paste the caffeine.fchk file to your machine.

Open the Multiwfn directory and double click the Multiwfn executable. Press enter and a GUI will pop up to choose the input file. Enter the following commands to navigate to the ELF calculation interface.

5 9

In case you want to change the size of the box within which the calculation is performed, enter -10 and the a number to control the box size. Choose one of the options 1, 2 or 3. Even the option with the smallest grid should run within several seconds.

Enter -1 and an isosurface plot of the ELF calculation is generated. When you press "Return", you can enter commands again. For example ??? saves the generated ELF data in .cube files, which can be used to visualise the calculation results in VMD.

Performing other calculations is straight forward as well. Just have a look at the manual!