1-2 Electron Spin
5
Figure 1-3: Orientations of spin angular momentum vectors for one and two electrons relative to
an external magnetic field directed along the z-axis. ħ = h/2π.
Diamagnetic and paramagnetic substances develop magnetic moments that are
respectively opposed to, and in the direction of an external magnetic field. The
magnetic moments for the paramagnetic molecules that we shall discuss in this
book arise either primarily or almost entirely from the presence of one or more
unpaired-electron spins, i.e. the total spin quantum number S is non-zero for such
a molecule. For a molecule with spin quantum number S, the spin angular
number n, it may be deduced that a maximum of 2n electrons may occupy each of n
independent circular orbits around the nucleus. There are n
2 atomic orbitals with principal
quantum number n. Therefore 2n n/n
2 = 2. The 2 n
2 = 2n n factorizations of 2n
2 give the
human identity
4f Pauli + Schrödinger = Heisenberg + Bohr!
5
Figure 1-3: Orientations of spin angular momentum vectors for one and two electrons relative to
an external magnetic field directed along the z-axis. ħ = h/2π.
Diamagnetic and paramagnetic substances develop magnetic moments that are
respectively opposed to, and in the direction of an external magnetic field. The
magnetic moments for the paramagnetic molecules that we shall discuss in this
book arise either primarily or almost entirely from the presence of one or more
unpaired-electron spins, i.e. the total spin quantum number S is non-zero for such
a molecule. For a molecule with spin quantum number S, the spin angular
number n, it may be deduced that a maximum of 2n electrons may occupy each of n
independent circular orbits around the nucleus. There are n
2 atomic orbitals with principal
quantum number n. Therefore 2n n/n
2 = 2. The 2 n
2 = 2n n factorizations of 2n
2 give the
human identity
4f Pauli + Schrödinger = Heisenberg + Bohr!