Psionic Weapon

Power Attack (PH) , STR 13,

Your melee weapon deals +1d4 points of damage (slashing, piercing, or bludgeoning, as appropriate to the weapon) when you pay the cost of 1 power point. You must decide whether or not to pay the cost prior to making the melee attack. Your weapon remains "charged" for a maximum number of rounds equal to your Strength modifier + 1, or until you make your next attack, whichever occurs first. If your attack misses, the power point expenditure is wasted.

You can charge your melee weapon with additional damage potential.