Quantum mechanics describes the microscopic properties of nature in a regime where classical mechanics no longer applies. It explains phenomena such as the wave-particle duality, quantization of energy and the uncertainty principle and is generally used in single body systems. Use the ...
Related is this question: Molecular and Atomic Orbitals and Antibonding. In my textbook on organic chemistry they represent an orbital as a 2d wave function to explain the formation of bonding and ...