Calculate the structure and frequencies of XH_n (X = H~Ne) by using B3LYP theoretical method with 6-31+G(d,p) then compare with the experimental values.

structure:

frequencies:

Calculate the single point energy of XH_n (X = H~Ne) by using CCSD(T) theoretical method with aug-cc-pVTZ ( the structure obtained from the previous homework ), and then use those energy to calculate the standard enthalpy of formation (ΔH°_f)  then compare with the experimental values.