%0 Journal Article %J J. Chem. Phys. %D 2017 %T Analytical derivatives of the individual state energies in ensemble density functional theory method. I. General formalism %A Filatov, Michael %A Liu, Fang %A Todd J. Martínez %B J. Chem. Phys. %V 147 %P 034113 %G eng %U https://aip.scitation.org/doi/abs/10.1063/1.4994542 %& 034113 %R https://doi.org/10.1063/1.4994542