Ground stateThe 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. If more than one ground state exists, they are said to be degenerate. Many systems have degenerate ground states.
Hydrogen atomA hydrogen atom is an atom of the chemical elementhydrogen. The electrically neutral hydrogen atom contains a single positively charged proton in the nucleus, and a single negatively charged electron bound to the nucleus by the Coulomb force. Atomic hydrogen constitutes about 74% of the baryonic mass of the universe. In everyday life on Earth, isolated hydrogen atoms (called "atomic hydrogen") are extremely rare.
Two-electron atomIn atomic physics, a two-electron atom or helium-like ion is a quantum mechanical system consisting of one nucleus with a charge of Ze and just two electrons. This is the first case of many-electron systems where the Pauli exclusion principle plays a central role. It is an example of a three-body problem.
Hartree–Fock methodIn computational physics and chemistry, the Hartree–Fock (HF) method is used for approximating the wave function and the energy of a quantum many-body system in a stationary state. It is named after Douglas Hartree and Vladimir Fock.
HeliumHelium (from Ancient Greek: ἥλιος, romanized: helios, lit. 'sun') is a chemical element; it has symbol He and atomic number 2. It is a colorless, odorless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. Its boiling point is the lowest among all the elements, and it does not have a melting point at standard pressures. It is the second-lightest and second-most abundant element in the observable universe, after hydrogen.
Schrödinger equationThe Schrödinger equation is a partial differential equation that governs the wave function of a non-relativistic quantum-mechanical system. Its discovery was a significant landmark in the development of quantum mechanics. It is named after Erwin Schrödinger, an Austrian physicist, who postulated the equation in 1925 and published it in 1926, forming the basis for the work that resulted in his Nobel Prize in Physics in 1933.
Isotopes of heliumStandard atomic weightAr°(He)4.002602±0.0000024.0026±0.0001 (abridged)Helium (2He) has nine known isotopes, but only helium-3 (He) and helium-4 (He) are stable. All radioisotopes are short-lived; the only particle-bound ones are He and He with half-lives 806.9 and 119.5 milliseconds. In Earth's atmosphere, the ratio of He to He is 1.37×10. However, the isotopic abundance of helium varies greatly depending on its origin, though helium-4 is always in great preponderance.
Quantum mechanicsDescription of physical properties at the atomic and subatomic scaleWave functions of the electron in a hydrogen atom at different energy levels. Quantum mechanics cannot predict the exact location of a particle in space, only the probability of finding it at different locations.
Closed-form expressionIn mathematics, a closed formexpression or formula is one that is formed with constants, variables, and a set of functions considered as basic and connected by arithmetic operations (+, −, ×, /, and integer powers) and function composition. Commonly, the basic functions that are allowed in closed forms are nth root, exponential function, logarithm, and trigonometric functions. However, the set of basic functions depends on the context.
Wave functionMathematical description of quantum stateQuantum harmonic oscillators for a single spinless particle. The oscillations have no trajectory, but are instead represented each as waves; the vertical axis shows the real part (blue) and imaginary part (red) of the wave function. Panels A–D show four different standing-wave solutions of the Schrödinger equation.
AtomSmallest unit of a chemical elementAtoms are the basic particles of the chemical elements and the fundamental building blocks of matter. An atom consists of a nucleus of protons and generally neutrons, surrounded by an electromagnetically bound swarm of electrons. The chemical elements are distinguished from each other by the number of protons that are in their atoms. For example, any atom that contains 11 protons is sodium, and any atom that contains 29 protons is copper.
Albrecht UnsöldAlbrecht Otto Johannes Unsöld (20 April 1905 – 23 September 1995) was a German astrophysicist known for his contributions to spectroscopic analysis of stellar atmospheres.
ElectromagnetismIn physics, electromagnetism is an interaction that occurs between particles with electric charge via electromagnetic fields. The electromagnetic force is one of the four fundamental forces of nature. It is the dominant force in the interactions of atoms and molecules. Electromagnetism describes and relates the three distinct but closely intertwined phenomena of electricity, magnetism, and optics.*As an Amazon Associate I earn from qualifying purchases.