Helmholtz free energy
kâruž-e âzâd-e Helmholtz
Fr.: énergie libre de Helmholtz
Of a system, the quantity whose decrease gives the maximum amount of external work which is performed when any physical or chemical process is carried out reversibly at constant temperature. It is defined by F = U - TS, where U is the → internal energy, T the → absolute temperature, and S the final → entropy.