Convert from electronvolt to libra [ancient Rome]

Unit Definition (electronvolt)
The electronvolt is a unit of mass used in particle physics. Mass and energy are related by Einstein's famous equation, E = mc². The constant c is the speed of light, 299.79 x 10E6 m/sec. An energy of 1 electronvolt is therefore equivalent to a mass of about 1.782 662 x 10E-33 gram, or about 1.073 544 x 10E-9 atomic mass unit.

Unit Definition (libra [ancient Rome])
The libra [ancient Rome] is a traditional unit of weight. The libra was the Roman unit from which the English pound is descended; the symbol "lb" for the pound comes from this unit. The Roman libra contained only 12 unciae (ounces) and was about 0.722 English pound. The word "libra" is sometimes used now for the kilogram, a much larger unit.