where 𝜒̅ 𝐴 0 is the isolated atom's reference value of electronegativity, which in this work, is take from , while ∆𝜒̅ 𝐴 is calculated as ∆𝜒̅ 𝐴 = 𝜒̅ 𝐴 -𝜒̅ 𝐴,𝑣𝑎𝑐 and 𝜒̅ 𝐴,𝑣𝑎𝑐 is the average atomic electron energy calculated for the isolated atom in vacuum. ∆𝜒̅ 𝐴 essentially rescales the standard electronegativity of the isolated atom.