Holy Radiance

 
Prerequisite(s): Cha 15+, Nimbus of Light
 
Benefit: At will, as a free action, you can empower the radiance around you into a blazing glow that sheds a 10' radius of bright light. Undead within 10' of you take 1d4 damage each round they stay in the light.
 
Source: Book of Exalted Deeds