Arcane Weapon

Coat your weapon in magical energy of a damage type used by one of your other spells or cantrips. If no such spells or cantrips are known, the Force damage type will be used. For the duration of the spell, add 1d4 of the chosen damage type to damage rolls with the weapon.
For every spell level above 1st, add an additional 1d4 damage of the chosen type.