in the window that opens choose first the Job Type tab and select Optimisation
then click on theMethod tab
on the "method" line select DFT, B3LYP should come up, then on the "basis set" line select 6-311G and click on the area in the brackets on the same line, picking d,p (red boxes).
you must also check the charge and multiplicity (blue box), Gaussview will make a guess at this for you, but can frequently get it wrong. You will need to always double check as this is very important, if in doubt ask a demonstator or myself what these values should be.
Charge is the overall charge on the molecule, it is zero for a neutral water molecule. The multiplicity is a quantum number for the total electron spin on a molecule J=2S+1 where S is the total spin momentum. Since in most systems there are even numbers of electrons S=0 is the norm, and then J=1 we call this a "singlet" system. Sometimes we still have an even number of electrons, but two will be unpaired and then S=1/2+1/2=1 and J=3, this is a "triplet" system. A radical has one unpaired electron and then S=1/2 and J=2 this is called a "doublet". Transition metal systems can routinely have up to 5 unpaired spins. Having all paired electrons is almost always the most stable and so you should check that this number is one.
then click on the Title tab an enter in a title for the job, be descriptive as in real research you can build up 1000's of files and this helps you keep track of what you calculated and why (red box)
you can see the title appear at the top of the box, just below this is the Keyword section (blue box), these are the keywords you have set using the graphical interface, you can also manipulate these directly vi the *.com file using vi/emacs.
now we need to submit the job, click on the Submit tab at the bottom right of this window
a new window will appear asking to save the file. Choose a descriptive name and save the file!
Gaussview is basically a graphical interface for manipulating the *.com and interpreting the *.log files. In submitting a job Gaussview takes the options you have selected and writes a *.com file.
Gaussview will then ask if you want to run the job, if you say yes it will run the job in your terminal on the login node of cx1. For this one job say yes ... however normally you shouldn't do this! Normally, we would assign the job memory and disk resources and submit the job into a queue.
when it is done you should get a window like this appear (in this case the job should take less than 5min (and probably only 1-2) it will depend a bit on the usage of the cx1 login node.
then choose to open the *.log file. A common error is to leave the *.com file open and then to use this file instead of the *.log file in a subsequent computation. To avoid this close *.com files when you submit a job, and double check that you are accessing a log file by looking at the path at the top of the opened file (top red box). It is also worth double checking the charge and multiplicity at this point too (bottom red box).
