The elemental opacities are calculated on a uniform grid of temperatures,
electron degeneracy paramaters and dimensionless photon energies **u**,
where **u** is defined as:

**u = hv / kT**

**hv** is the photon energy in eV and **kT** is the temperature in eV.
The **u** grid is selected instead of the photon energy grid because
the same **u** grid can be used for all temperatures and cover the
important photon energy ranges needed to integrate the Rosseland and
Planck "gray" opacities. These photon energy ranges would be 0. - 20. eV
for a temperature of 1. eV and 0. - 2000. eV for a 100. eV temperature.
For the **u** grid, the range would be 0. - 20. for both temperatures.

**u Grid used on the Web Page**

The opacities are calculated on a grid of 14,900 **u** points for each
temperature point. This grid is shown below:

**
**

u Values 14,900 Point Grid _________ ___________________________ 0.0 | | 9600 points, steps of .00125 | 12.5 | | 1600 points, steps of .005 | 20.0 | | 1000 points, steps of .01 | 30.0 | | 700 points, steps of .1 | 100.0 | | 900 points, steps of 1.0 | 1000.0 | | 900 points, steps of 10.0 | 10000.0 | | 200 points, steps of 100.0 | 30000.0 _____ 14900 points