Question

Calculate the energetic contribution of the electrostatic interaction between the R38 NH1 atom and the D6 OD1 atom. The distance between NH1 and OD1 is 3.49 Å.  NH1 can be assumed to have a partial charge of +0.33 and OD1 a partial charge of -0.5.  Use a distant dependent dielectric in your calculation.  Provide your answer in units of kcal/mol.

Answer 1

Given

partial charge on NH1 atom = +0.33

partial charge on OD1 is = -0.5

distance between NH1 and OD1 is 3.49^oA

= 3.49 X 10^-10 m

thus, interaction energy is

E = Kqq / r²

= [(9 X 10⁹ )X (-0.5) X (0.33)] / (3.49 X 10^-10)²

= 0.122 X 10²⁹ J

1 Joule = 0.000239 kilocalorie

= 2.91 X 10²⁴ kcal

= 1 mole = 6.022 X10²³ units of a substances

=2.91 X 10²⁴ X 6.022 X 10²³ Kcal/mol

= 1.752 X10⁴⁸ Kcal/mol