Are you asking about plotting the summary results of an IRC calculation?  GaussView can do this.  To adjust the 0 of the vertical axis so that reactant energy is 0, you should copy the results from Gaussian output to Excel (or some other spreadsheet program), split the text into columns, and adjust the energy.  After that, the results can be plotted in Excel itself.

Dear Ram

I was asking about the plot where we put the energy levels of the reactant, product, ts and intermediates. And after that we connect them via dashed line.

You can use origin software to plot. take the energy values of reactant, product, ts and intermediates, and get the activation energy (TS-react), reaction energy (prod-react) and set ur reactant energy as 0 and plot....

Or else you can draw it in powerpont itself using picture tools as u know what is ur barrier height and product- reactant difference. this may help you...you can find this kind of drawings in OL papers.

I agree with Choutipalli. Origin is super expensive, though. I have used something called PSI Plot to generate these figures.  However, it is rarely necessary to be quantitative in such plots -- one just needs to show the relative energies. Put down the numbers on each horizontal line to show the actual values. PowerPoint will do the job.

I have developed a free application designed for plotting 2D PES graphs, one can find more about it at:

github.com/ricalmang/mechaSVG

Attached here is one example of a graph plotted using this application.

origin or chemdraw

Ricardo Almir Angnes : Awesome application. Very useful to several of us. Windows security had a bit of a heart-attack when I tried to install, but I got past that. :-)