You can channel energy to deal extra damage against undead in melee.
Prerequisites: Turn undead ability.
Benefit: As a free action, spend one of your turn undead attempts to add 2d6 points of damage to all your successful melee attacks against undead until the end of the current round.
Source: Complete Warrior, page 108. As the feat name begins with the word “Sacred” (as opposed to “Profane”) and the description text under Benefit mentioned only turn undead, rebuke undead references have been removed from the prerequisites. Republished in Libris Mortis, page 30.