Adjacency
matrices

•Label

Label the atoms in the molecule, starting from
1:

1

1

Create a matrix whose entries are 1 if edges
are adjacent, 0 otherwise

A=

Schrodinger’s Equation reads

A
ψ = λ ψ ,

i.e. an *eigenvalue* equation

Upshot: Eigenvalues of A are energy levels,

Eigenfunctions are wave-functions