Question

Discuss the role of the Born-Oppenheimer approximation in the e-bond calculation of a molecular potential energy curve or surface. valence-bong

Answer 1

The Schrödinger equation does not solve for all molecular systems. However, it is possible to solve the equation exactly for the simplest type of molecule, H2 +, when the electron motion is separated from the nuclear motion in accordance with Ben-Obheimer's approximation. The mass of the atom is much larger than that of the electron molecule (the rest of the atom is proton heavier than the rest of the electron atom). This means that the electron can adapt almost immediately to any change in the position of the nucleus. Therefore, the electrical wave function depends only on the position of the nucleus and does not depend on its timing. As Rodin-Oppenheimer approaches, the whole wave function of the molecule can be written in the following form:

1.10

Total energy is equal to the sum of nuclear energy. Electrostatic energy includes kinetic energy and the potential of moving electrons in the electromagnetic field of the nucleus, along with the electron rejection: ETOT = E (electron) + E (nuclear). When using the Rodin-Oppenheimer approximation, we focus on electronic motion; The core is considered constant. For each nucleus arrangement, the Schrödinger equation is solved only for the electrons in the nuclear part. If you want to change the nuclear position then you need to add the nuclear force to the electrical energy to calculate the total configuration energy.