Manual for AIMAll (Version 14.11.23)

This tutorial shows how to display properties at / of critical points of the electron density distribution.

1. In AIMStudio, select Run->AIMQB to launch an AIMQB Dialog.



2. In the AIMQB Dialog, Browse to the folder C:\AIMAll\test\cyclicformamide and select the file cyclicformamide.wfn and then click the "Open" button to start an AIMAll numerical analysis of cyclicformamide.wfn



3. Wait a few seconds, until the Rho critical point analysis (via AIMExt) is done and the atomic integrations (via AIMInt) have begun.  Since we are only interested in the Rho critical point results, we needn't wait for the atomic integrations to finish.



4. Select the "File->Open in New Window" menu item and open the file cyclopropanone.mgpviz







5. Check the "BCPs->Properties->Rho" menu item to show the electron density value at each of the bond critical points (BCPs).





6. Note that the electron density at the O2|H11 and O8|H5 BCPs is much smaller than at the other BCPs.  In fact, the electron density at these BCPs is sufficiently small that the bond paths and ring paths associated with them are drawn as dashed paths instead of solid paths to indicate the weak nature of these BCPs.  The electron density threshold value for defining "weak" bond critical points is 0.025 a.u. by default but this value can be adjusted by selecting the "View->Weak CP Threshold" menu item.  We will accept the default value here.



7. Check the "RCPs->Properties->Rho" menu item to show the electron density value at the single ring critical point (RCP) in the molecule.  Also, check the menu item "BCPs->Properties->Text-->Placement->Bottom".







Note that the electron density at the RCP is necessarily less than the value at any of the BCPs it is connected to.

8. Hide the electron density at the RCP again by checking the "RCPs->Properties->None" menu item.
    
9. Show the Laplacian of the electron density (DelSqRho) at the BCPs by checking the "BCPs->Properties->Hessian of Rho->DelSqRho" menu item.
    
10. Only show the DelSqRho values at the symmetrically unique BCPs that involve hydrogens by checking the menu item "BCPs->Properties->Mode->Selected BCPs" and then clicking on the C7|H10, N9|H11, O2|H11 and N9|H11 BCPs.







Note that the value of the Laplacian of Rho at the O2|H11 BCP is relatively small and positive, which is characteristic of such weak bonding interactions.

11. Make the BCP property text in the window white by the selecting the menu item "BCPs->Properties->Text->Font Color...".  Also, change the font of the BCP property text to Arial/Bold/12 by selecting the menu item "BCPs->Properties->Text->Font...".

    

    

    Note that the Font and Font Color of the Legend have also been changed (to be the same as the BCP property text) via the corresponding "View->Legend" menu items.