Sharp nS→2P
Principal nP→2S
Diffuse nD→2P
Baseline system (fundamental) nF→3D
This notation comes from the terminology of spectroscopy. Spectral analysis is an important means to study the structure of atoms and molecules. The above line systems are respectively generated from orbital transitions with orbital quantum numbers l = 0, 1, 2, and 3, so these orbits are named with the initials s, p, d, and f.
Because this new concept is different from the idea of ??orbit in classical physics, in 1932 the American chemist Robert Mulliken proposed to replace the word "orbit" with "orbital".
Atomic orbit is the wave function of a single atom. When used, three quantization parameters, n (principal quantum number), l (angular quantum number), and m (magnetic quantum number), must be substituted to determine the electron's Energy, angular momentum and orientation are collectively called quantum numbers.
Each orbital has a different set of quantum numbers and can hold up to two electrons. S orbitals, p orbitals, d orbitals, and f orbitals represent orbits with angular quantum numbers l=0, 1, 2, and 3 respectively, showing the orbital shape and electron arrangement as shown on the right.
Its name comes from the description of the appearance of the characteristic lines of its atomic spectrum, which are divided into sharp spectrum (sharp), principal spectrum (principal), diffuse spectrum (diffuse), and basic spectrum ( fundamental), and the rest are named in alphabetical order (j is skipped).
In calculations in atomic physics, complex electron functions are often simplified into easier combinations of atomic orbital functions. Although the electrons of multi-electron atoms cannot be explained by the ideal image of "atomic orbitals of one or two electrons".
Its wave function can still be decomposed into a combination of atomic orbital functions and analyzed based on atomic orbital theory; just like in a sense, the electron cloud composed of multi-electron atoms is still based on Atomic orbitals are "made up", and each atomic orbital contains only one or two electrons.
Extended information
Energy level splitting:
In multi-electron atoms, when valence electrons enter the real interior of the atom, the inner electrons shield the nucleus Decreasing is equivalent to an increase in the actual effective charge number of the atom, which means that the gravitational force on the electron increases and the system energy of the atom decreases, so it can be easily concluded from this.
When the principal quantum number n is the same, the atomic orbital shapes corresponding to different orbital angular momentum numbers l are different. That is, when the valence electrons are in different orbits, the energy reduction of the atom is also different. The more obvious the orbit penetration effect, the greater the energy reduction.
The energies of s, p, d, and f energy levels are different in size. This phenomenon is called "energy level splitting". The main reason for the shielding effect is the mutual repulsion of electrostatic forces between electrons outside the nucleus. , weakening the attraction of the atomic nucleus to electrons: electrons at the s energy level repel electrons at the p energy level, "pushing" the p electrons away from the nucleus, and there is a similar situation between p, d, and f
General shielding The order is: ns>np>nd>nf
Because the farther away from the nucleus, the greater the energy, so the energy order is inversely proportional to the shielding order
The energy order is: ns Baidu Encyclopedia--Atomic Orbitals