# Gaussian(Software): What does atomic orbital contribution mean? [closed]

Example Molecule: C60 (Fullerene)

Route Section: #p B3LYP/6-311G(d) guess = read geom = check pop = full

Question: What information can I get from atomic orbital contributions?

I've calculated atomic orbital contribution of molecule with following procedure: The keyword 'pop=full' gives all atomic orbital coefficients, composing molecular orbitals. So I did absolute sum of S orbitals(1s,2s,3s)' coefficients, P orbitals(2px,2py,...,3pz)' coefficients, and D orbitals' coefficients denoted by S_coef, P_coef, and D_coef respectively. Then I defined the contribution of S, P, and D by

$$S_{contri} = \frac{S_{coef}}{S_{coef} + P_{coef} + D_{coef}}$$

(As you may noticed, P and D contribution is nothing but replacing the numerator with its coefficients)

The result is following: X axis is molecular numbers and y axis is contribution of S, P, D atomic orbitals of C60. And its Homo is at the 180th orbital on the x axis. I find the result reasonable, since S_contribution is greater in the group of inner molecular orbitals(small orbital numbers), and P_contribution become dominant as the molecular number gets greater. But I am afraid if there is something that i missed from the result. Otherwise, Is it just OK to check which atomic orbital is dominant near HOMO or inner shell?

• I gave my +1 long ago, but just wanted to check how things are going for you with this problem? Have you figured out the answer? Have you made any progress? Are you still working on it? Please update us! Feb 18 at 5:31