D&Dtools1

You cause a weapon to gain the ability to deal energy damage in addition to its other abilities, similar to how a flaming burst weapon deals extra fire damage on a hit or critical hit.
The weapon can deal acid, cold, electricity, fire, or sonic damage, chosen by you at the time of casting.
The weapon deals +1d6 damage of that energy type on a successful hit.
On a critical hit, the weapon deals an additional +1d10 points of energy damage.
If the weapon's critical multiplier is x3, add +2d10 points of energy damage instead, and if the multiplier is x4, add +3d10 points of bonus energy damage.
This spell can be cast on a weapon that already deals energy damage, but if the weapon already creates the same type of damage as the spell, the effects do not stack.
For example, if cast on a +1 flaming longsword to give it additional fire damage, the spell has no effect, but it can give the weapon any of the other types of energy damage.
This spell has a subtype that is the same as the energy created by the target weapon.
For example, weapon of energy is a fire spell when used to give a weapon bonus fire damage.