Quintal definition: a unit of weight equal to 100 pounds | Meaning, pronunciation, translations and examples English Dictionary | Thesaurus | Translator | Grammar | Scrabble | Blog English
Electrons in a hydrogen atom must be in one of the allowed energy levels. If an electron is in the first energy level, it must have exactly -13.6 eV of energy. If it is in the second energy level, it must have -3.4 eV of energy. An electron in a hydrogen atom cannot have -9 eV, -8 eV or any other value in between. Let's say the electron wants to jump from the first energy level, n = 1, to the second energy level n = 2. The second energy level has higher energy than the first, so to move from n = 1 to n = 2, the electron needs to gain energy.
This is due to the exchange antisymmetry and the effect of the spin state on the spatial state (as in ferromagnetism). The first diagram below shows the result of our calculation. All states increase in energy due to the Coulomb repulsion of the electrons. Before the perturbation, the first excited state is degenerate. After the perturbation, the singlet and triplet spin states split significantly due to the symmetry of the spatial part of the wavefunction. We designate the states with the usual spectroscopic notation.