Helium-4 (4 He ) is a stable isotope of the element helium. It is by far the more abundant of the two naturally occurring isotopes of helium, making up...

nuclear binding energy (per nucleon) of helium-4, with respect to the next three elements after helium. This helium-4 binding energy also accounts for why...

Superfluid helium-4 (helium II or He-II) is the superfluid form of helium-4, an isotope of the element helium. A superfluid is a state of matter in which...

Helium-3 (3He see also helion) is a light, stable isotope of helium with two protons and one neutron. (In contrast, the most common isotope, helium-4...

there are nine known isotopes of helium (2He) (standard atomic weight: 4.002602(2)), only helium-3 (3 He ) and helium-4 (4 He ) are stable. All radioisotopes...

Liquid helium is a physical state of helium at very low temperatures at standard atmospheric pressures. Liquid helium may show superfluidity. At standard...

protons and two neutrons bound together into a particle identical to a helium-4 nucleus. They are generally produced in the process of alpha decay but...

universe's helium (as isotope helium-4 (4He)), along with small fractions of the hydrogen isotope deuterium (2H or D), the helium isotope helium-3 (3He)...

nuclear fusion reactions by which three helium-4 nuclei (alpha particles) are transformed into carbon. Helium accumulates in the cores of stars as a result...

include the photon and atoms with an even number of neutrons (such as helium-4 (4 He )), are allowed to share a quantum state. Einstein proposed that cooling...

cooling of helium-4 (the more common isotope of helium), a 1-K pot liquefies a small amount of helium-3 in a small vessel called a helium-3 pot. Evaporative...

characteristic manner described by Bose–Einstein statistics: for example a gas of helium-4 atoms becomes a superfluid at temperatures close to absolute zero. Similarly...

known sets of nuclear fusion reactions by which stars convert hydrogen to helium. It dominates in stars with masses less than or equal to that of the Sun...

nuclear fission. Nuclear fusion uses lighter elements, such as hydrogen and helium, which are in general more fusible; while the heavier elements, such as...

composite and wide spectral lines and helium with the inherently wide spectral line. Magnetometers based on helium-4 excited to its metastable triplet state...

averages. For example, an atom of helium-4 has a mass of 4.0026 Da. This is an intrinsic property of the isotope and all helium-4 atoms have the same mass. Acetylsalicylic...

The helium hydride ion, hydridohelium(1+) ion, or helonium is a cation (positively charged ion) with chemical formula HeH+. It consists of a helium atom...

region. The cooling power is provided by the heat of mixing of the helium-3 and helium-4 isotopes. The dilution refrigerator was first proposed by Heinz...

involve more than one solid phase, for substances with multiple polymorphs. Helium-4 is unusual in that it has no sublimation/deposition curve and therefore...

rotate indefinitely. Superfluidity occurs in two isotopes of helium (helium-3 and helium-4) when they are liquefied by cooling to cryogenic temperatures...

Stellar nucleosynthesis has occurred since the original creation of hydrogen, helium and lithium during the Big Bang. As a predictive theory, it yields accurate...

number 4; it is therefore also helium-4. The complete equation therefore reads: 6 3Li  + 2 1H  → 4 2He  + 4 2He . or more simply: 6 3Li  + 2 1H  → 2 4 2He...

California Radiation Laboratory) by bombarding curium with alpha particles (helium-4 ions). It is an actinide element, the sixth transuranium element to be...

A helium atom is an atom of the chemical element helium. Helium is composed of two electrons bound by the electromagnetic force to a nucleus containing...

Helium is the smallest and the lightest noble gas and one of the most unreactive elements, so it was commonly considered that helium compounds cannot exist...

H.; et al. (STAR Collaboration) (2011). "Observation of the antimatter helium-4 nucleus". Nature. 473 (7347): 353–356. arXiv:1103.3312. Bibcode:2011Natur...

heavier elements, initially deuterium which itself quickly fuses into mainly helium-4. By 20 minutes, the universe is no longer hot enough for nuclear fusion...

the helium-3 isotope, consisting of two protons and one neutron. The nucleus of the other (and far more common) stable isotope of helium, helium-4, consisting...

The helium dimer is a van der Waals molecule with formula He2 consisting of two helium atoms. This chemical is the largest diatomic molecule—a molecule...

A helium flash is a very brief thermal runaway nuclear fusion of large quantities of helium into carbon through the triple-alpha process in the core of...