HOMO-LUMO gap is a number. Any idea how to visualize one single number? =)

In general http://lmgtfy.com/?q=gaussview+video+tutorials

Dear Oleg Gromov I meant like in semiconductor we plot bandstructure in which we see valance band maxima and conduction band mnima positions. After that by calculating gap between these two in terms of energy, we say this is the bandgap of respected system.

I wanted to ask same thing we can do for molecule.

Thank You

Shilendra

Gaussview supports copy/paste with Ctrl+C/Ctrl+V.

With this you can easily build clusters of whatever number of H2O2 molecules you want.

As for the HOMO-LUMO gap, to the best of my knowledge Gaussview doesn't plot the electronic Density of States (eDoS).

I suggest using another software like Multiwfn that can extract the eDoS from Gaussian's chk files.

From the eDoS it's easy to visualize the HOMO-LUMO gap.

Thank You Dr. Francesco Muniz-Miranda for your help and suggestions. I will try to use Multiwfn software.

Shilendra

The molecular orbital diagram including HOMO-LUMO gap can indeed be 'visualize' by gaussview. Just open the output file (.log or .out) and go to the MO editor (see attached screenshot for water). The HOMO and LUMO state will be highlighted by default. If you want to visualize the individual orbitals then you've to open the checkpoint (.chk) file with gview and then use the surface/contour option to generate the cube file and render the orbital.If you need something like TDOS or pDOS you've to use Multiwfn as Francesco has suggested.

Thank you dear Turbasu Sengupta for clear explanation. Can you tell me how to generate cube file from Gaussian software, I am using command based linux Gaussian. From manual I did not get how to use Gaussian utilities.

Shilendra

Dear Shilendra,

There are two different ways by which you can generate .cub file in Gaussian09. First one is the easy way which is via Gview (recommended for non expert users). See the attached files for this method. Second method is via Gaussian utilities in command mode as you've mentioned. The steps to generate .cub file via gaussian utilities is given below.

1. First convert the .chk file to .fchk file through formchk utilities. e.g if the checkpoint file is h2o.chk then the command to generate .fchk file is:

formchk h2o.chk h2o.fchk

2. After the .fchk file is generated now you can proceed to generate .cub file. The command format for common cases is :

cubegen nprocs type fchkfilename cubefilename gridquality

where nprocs=number of processor should be used to generate cube file (default=1)

type= type of cube file, MO,total density , alpha density etc..

 fchkfilename and cubefilename = the respective .fchk (input)  and .cub file (output) names.

gridquality= values -2, -3 and -4 correspond to the keywords Coarse, Medium and Fine.

e.g: if you want to generate the .cub file of HOMO of H2O (MO number 5), the commands are 

Step 1.         formchk h2o.chk h2o.fchk

Step 2.         cubegen 1 MO=5 h2o.fchk homo.cub -3

Now the cube file (named homo.cub) will be generated. You can open it in any software like avogadro,chemcraft etc.

see http://www.gaussian.com/g_tech/g_ur/u_cubegen.htm  for further details and for additional options. 

Sorry to bother you again. Hope your problem of generating structure of Dimer,trimer etc. from monomer is already solved. If not, the attached screenshots will help you to generate them in Gview. This tutorial is done for H2O tetramer and utilizes the copy/paste function of Gview. There are also alternative ways by which the same can be done.

Thank you dear Turbasu Sengupta for help and support and spending time for my queries. I will try all these steps and methods as you mentioned in your post.

Shilendra

Dear all RG colleagues,

Nice to share the outstanding guide about "How to use GaussView" as follows:

1) https://www.mtholyoke.edu/courses/jwijngaa/PS/Gaussview2.pdf

2) https://www.tau.ac.il/~ephraim/intro2gaussview.pdf

3) https://gaussian.com/gv6main/

Have a good day!!!@@