Subject: G94 cube file units and Cerius2

From: Nathalie Godbout <[email-masked]>
Date: Tue, 11 Aug 1998 16:38:27 -0500 (CDT)

Dear computational chemists,

     I have a question concerning electron density surfaces 
calculated with G94 (cube=density), the use of Cerius2 to
display these surfaces and units. 

     According to the cube file I have calculated, the density
values range from 0 to 27 electrons/bohr^3 (I think). When I
use the Gaussian interface in Cerius2 to display the surface,
the property range displayed is 0 to 182. Using the conversion 
factor between electrons/bohr^3 and electrons/angstrom^3 (6.75),
I get the the property range displayed in Cerius2. To make sure
this was correct, I created a 3X3X3 cube with only one non-zero value, namely 1.0.
When I display this cube in Cerius2, I expected the property to range
from 0 to 6.75 e/A^3. I get that the range is 0 to 1.0. Further, I am
able to display electron density values between 0.0 and 1.0. 

    Are the values in the cube file multiplied by a conversion factor
or are values extra/intrapolated?

   I have also the same question for the electrostatic potential for which
there is also a difference the cube file values and the displayed
values. 

   I will summarize.

   Thank you for your help.

       Nathalie

 --------------------------------------------
| Nathalie Godbout                           |
| University of Illinois at Urbana-Champaign |
| 600 S. Goodwin Av. Box 23.6                |
| Urbana, IL 61801                           |
 --------------------------------------------