Step 8: Analysis: The sigma profile

Select Analysis → Sigma Profile
In the left part of the window select 'water' for compound '1'
Select 'ethanol' for compound '2'
Select 'benzene' for compound '3'
Select 'methanol' for compound '4'
Select File → Run
Click 'Yes' when asked to 'Save changes (required to run)?'
Enter the name 'tutorial2' in the 'Filename' field

The sigma profiles (σ-profile) of the three pure compounds will be shown in a graph and in a table in the right part of the window. The whole window can be resized. The relative size of the left part of the window compared to the right part can be changed if one moves the sash that is in between these parts. In the right part of the window one can also change the relative size of the upper part compared to the lower part if one moves the sash that is in between these parts.

The σ-profile shows the amount of surface area for a given COSMO charge density. If the default settings are used, the red curve is the water σ-profile, the blue curve the methanol σ-profile, the green curve is the benzene σ-profile, and the yellow curve the methanol σ-profile. If one clicks in the graph one can zoom (right mouse, or Command-Left (drag up or down)), or translate (left mouse) the graph. If one clicks in the graph window at the left or below the axes, a popup window will appear in which one can set details for the graph window.

Note that the σ-profile depends on the method (COSMO-RS or COSMO-SAC) that was used in the calculation. Here we have used COSMO-RS. In this case the σ-profile depends on the actual value for r_av (r_av), which is one of the COSMO-RS parameters, see one of the previous steps.

One can also look at the hydrogen bonding part of the σ-profile.

In the left part of the window select 'Pure: HB' for Solvent
Press 'Run'