Default color scale
Spartan02 uses color to show the value of the potential
at different points on the map. Each potential corresponds to a
unique color, and you “read” a map by noticing where
different colors appear.
Spartan02 can select colors automatically or it can
select colors according to instructions that you give it (see below).
When Spartan02 is allowed to select colors automatically, it is
uses a default color scale to equate different potentials
with different colors.
First, the program surveys all of the potentials on
the map, and finds the most negative and most positive potentials.
These regions are colored red and dark blue, respectively. Intermediate
potentials are then assigned colors according to the standard color
red (most negative) < yellow
< green < light blue
< dark blue (most positive)
To make these color relationships clearer, consider
the potential map of water that was depicted in the previous figure.
The potentials on this map range from -46 to +48 kcal/mol. The red
region near oxygen shows the location of the most negative potential,
-46 kcal/mol (this region attracts the +1 probe). The dark blue
regions near the hydrogens show the locations of the most positive
potential, +48 kcal/mol (these regions repel the +1 probe).
The green region shows the location of the mean potential,
the average of the two extremes. On this map, the mean potential
is +1 kcal/mol. The yellow region and light blue regions show the
locations of potentials halfway between the mean (green) and extremes
(red and dark blue). On this map, yellow corresponds to -22 kcal/mol
and light blue corresponds to +24 kcal/mol.