Energy levels for an electron in an atom: ground state and excited states. After absorbing energy, an electron may jump from the ground state to a higher-energy excited state.
The ground state of a quantum-mechanical system is its stationary state of lowest energy; the energy of the ground state is known as the zero-point energy of the system. An excited state is any state with energy greater than the ground state. In quantum field theory, the ground state is usually called the vacuum state or the vacuum.
If more than one ground state exists, they are said to be degenerate. Many systems have degenerate ground states. Degeneracy occurs whenever there exists a unitary operator that acts non-trivially on a ground state and commutes with the Hamiltonian of the system.
According to the third law of thermodynamics, a system at absolute zero temperature exists in its ground state; thus, its entropy is determined by the degeneracy of the ground state. Many systems, such as a perfect crystal lattice, have a unique ground state and therefore have zero entropy at absolute zero. It is also possible for the highest excited state to have absolute zero temperature for systems that exhibit negative temperature.
The groundstate of a quantum-mechanical system is its stationary state of lowest energy; the energy of the groundstate is known as the zero-point energy...
In American politics, a swing state (also known as battleground state, toss-up state, or purple state) is any state that could reasonably be won by either...
significance. For example, the electron configuration of the titanium groundstate can be written as either [Ar] 4s2 3d2 or [Ar] 3d2 4s2. The first notation...
approximations, such as the Hartree–Fock method, can be used to estimate the groundstate energy and wavefunction of the atom. Historically, the first such helium...
excited state of a system (such as an atom, molecule or nucleus) is any quantum state of the system that has a higher energy than the groundstate (that...
of the electron from the groundstate of the atom to the Volkov states. In this model the perturbation of the groundstate by the laser field is neglected...
investigate the electronic structure (or nuclear structure) (principally the groundstate) of many-body systems, in particular atoms, molecules, and the condensed...
accessible microstates, and there is typically one unique state (called the groundstate) with minimum energy. In such a case, the entropy at absolute zero will...
either The groundstate, with energy E1; or The excited state, with energy E2, with E2 > E1. The number of these atoms which are in the groundstate is given...
elements where the ground-state electron configuration changes within a column, where exceptions to Hund's rules occur. Groundstate term symbols for the...
Third, the lowest achievable energy (the energy of the n = 0 state, called the groundstate) is not equal to the minimum of the potential well, but ħω/2...
The groundstate of most molecules is a singlet state, denoted as S0. A notable exception is molecular oxygen, which has a triplet groundstate. Absorption...
spontaneously. The half-life of a nuclear isomer can even exceed that of the groundstate of the same nuclide, as shown by 180m 73Ta as well as 186m 75Re , 192m2...
in the groundstate. If it is at a higher energy level, it is said to be excited, or any electrons that have higher energy than the groundstate are excited...
the quantum-mechanical description, matter at absolute zero is in its groundstate, the point of lowest internal energy. The laws of thermodynamics indicate...
Majumdar–Ghosh groundstate are paired into a singlet, or valence bond, the three spins together can never be found to be in a spin 3/2 state. In fact, the...
needed to cool the mechanical resonator until it was in its quantum groundstate, the state with the lowest possible energy. A temperature T ≪ h f k {\displaystyle...
subatomic particle) transits from an excited energy state to a lower energy state (e.g., its groundstate) and emits a quantized amount of energy in the form...
molecule is a singlet state. It is a gas with physical properties differing only subtly from those of the more prevalent triplet groundstate of O2. In terms...
be promoted from a vibrational and electronic groundstate to a vibrational and electronic excited state. A third rule is the Laporte Rule, which necessitates...
absolute zero temperature, the system is in the state with the minimum thermal energy, the groundstate. The constant value (not necessarily zero) of entropy...
'building-up principle'), also called the Aufbau rule, states that in the groundstate of an atom or ion, electrons first fill subshells of the lowest available...
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