Helmenstine holds a Ph. De Broglie also postulated a general formula for obtaining the wavelength of a moving object. This computational affordability and often comparable accuracy to MP2 and CCSD T post-Hartree—Fock methods has made it one of the most popular methods in computational chemistry. Pioneering applications of this in chemistry were performed by Rice and Ramsperger in and Kassel in , and generalized into the RRKM theory in by Marcus who took the transition state theory developed by Eyring in into account. The coupling terms are called vibronic couplings. Quantum algorithms Quantum amplifier Quantum bus Quantum cellular automata Quantum finite automata Quantum channel Quantum circuit Quantum complexity theory Quantum computing Timeline Quantum cryptography Quantum electronics Quantum error correction Quantum imaging Quantum image processing Quantum information Quantum key distribution Quantum logic Quantum logic gates Quantum machine Quantum machine learning Quantum metamaterial Quantum metrology Quantum network Quantum neural network Quantum optics Quantum programming Quantum sensing Quantum simulator Quantum teleportation. In the valence bond model, we think of atomic orbitals on each of two atoms combining to form a bond orbital, with one electron from each atom occupying this orbital. Quantum chemistry is a branch of chemistry that focuses on rationalizing and explaining the behavior of subatomic particles like electrons. This phenomenon, known as diffraction, cannot be explained using a particle model for light.