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CHEM 121 Studioby Learn4Less · UBC CHEM 121

CHEM 121 glossary

Wavefunction

The mathematical function ψ\psi that describes a quantum particle such as an electron. ψ\psi itself can be positive or negative; its square ψ2\psi^2 gives the probability density of finding the particle at each point.

Particle-in-a-box wavefunction ψWavefunction between walls at x = 0 and x = L with 3 lobes and 2 interior nodes (marked with circles).V = ∞V = ∞0Lxψ

ψ3\psi_3 in a box: lobes of opposite sign separated by 2 nodes.

Example

For a particle in a box ψn=2/L sin⁡(nπx/L)\psi_n = \sqrt{2/L}\,\sin(n\pi x/L). The sign of ψ2\psi_2 flips at the centre; in atoms the same sign changes decide whether orbitals overlap constructively in bonding.

See alsoProbability densityNodeAtomic orbitalParticle in a box