08-09-2021-0045 - Ion Source

 An ion source is a device that creates atomic and molecular ions.^[1] Ion sources are used to form ions for mass spectrometers, optical emission spectrometers, particle accelerators, ion implanters and ion engines.

https://en.wikipedia.org/wiki/Ion_source

08-09-2021-0044 - Duoplasmatron

The Duoplasmatron is an ion source in which a cathode filament emits electrons into a vacuum chamber.^[1] A gas such as argon is introduced in very small quantities into the chamber, where it becomes charged or ionized through interactions with the free electrons from the cathode, forming a plasma. The plasma is then accelerated through a series of at least two highly charged grids, and becomes an ion beam, moving at fairly high speed from the aperture of the device.

https://en.wikipedia.org/wiki/Duoplasmatron

08-09-2021-0022 - Tritium, Trihydrogen Cation, Helium Hydride Trihydrocats, tritons, dihydrocat, ion hel hyride, helios, etc.

Tritium (/ˈtrɪtiəm/ or /ˈtrɪʃiəm/, from Ancient Greek τρίτος (trítos) 'third') or hydrogen-3 (symbol T or 3H) is a rare and radioactiveisotope of hydrogen. The nucleus of tritium (sometimes called a triton) contains one proton and two neutrons, whereas the nucleus of the common isotope hydrogen-1 (protium) contains just one proton, and that of hydrogen-2 (deuterium) contains one proton and one neutron.

Naturally occurring tritium is extremely rare on Earth. The atmosphere has only trace amounts, formed by the interaction of its gases with cosmic rays. It can be artificially produced by irradiating lithium metal or lithium-bearing ceramic pebbles in a nuclear reactor, and is a low-abundance byproduct in normal operations of nuclear reactors.

Tritium is used as the energy source in radioluminescent lights for watches, gun sights, numerous instruments and tools, and even novelty items such as self-illuminating key chains. It is used in a medical and scientific setting as a radioactive tracer. Tritium is also used as a nuclear fusion fuel, along with more abundant deuterium, in tokamak reactors and in hydrogen bombs.


https://en.wikipedia.org/wiki/Tritium

The trihydrogen cation or protonated molecular hydrogen is a cation (positive ion) with formula H+
3, consisting of three hydrogen nuclei (protons) sharing two electrons.

The trihydrogen cation is one of the most abundant ions in the universe. It is stable in the interstellar medium (ISM) due to the low temperature and low density of interstellar space. The role that H+
3 plays in the gas-phase chemistry of the ISM is unparalleled by any other molecular ion.

The trihydrogen cation is the simplest triatomic molecule, because its two electrons are the only valence electrons in the system. It is also the simplest example of a three-center two-electron bond system.

The three hydrogen atoms in the molecule form an equilateral triangle, with a bond length of 0.90 Å on each side. The bonding among the atoms is a three-center two-electron bond, a delocalized resonance hybrid type of structure. The strength of the bond has been calculated to be around 4.5 eV (104 kcal/mol).[15]
Isotopologues[edit]

In theory, the cation has 10 isotopologues, resulting from the replacement of one or more protons by nuclei of the other hydrogen isotopes; namely, deuterium nuclei (deuterons, 2
H+) or tritium nuclei (tritons, 3
H+). Some of them have been detected in interstellar clouds.[16] They differ in the atomic mass number A and the number of neutrons N:
H+
3 = 1
H+
3 (A=3, N=0) (the common one).[17][16]
[DH
2]+ = [2
H1
H
2]+ (A=4, N=1) (deuterium dihydrogen cation).[17][16]
[D
2H]+ = [2
H
21
H]+ (A=5, N=2) (dideuterium hydrogen cation).[17][16]
D+
3 = 2
H+
3 (A=6, N=3) (trideuterium cation).[17][16]
[TH
2]+ = [3
H1
H
2]+ (A=5, N=2) (tritium dihydrogen cation).
[TDH]+ = [3
H2
H1
H]+ (A=6, N=3) (tritium deuterium hydrogen cation).
[TD
2]+ = [3
H2
H
2]+ (A=7, N=4) (tritium dideuterium cation).
[T
2H]+ = [3
H
21
H]+ (A=7, N=4) (ditritium hydrogen cation).
[T
2D]+ = [3
H
22
H]+ (A=8, N=5) (ditritium deuterium cation).
T+
3 = 3
H+
2 (A=9, N=6) (tritritium cation).

The deuterium isotopologues have been implicated in the fractionation of deuterium in dense interstellar cloud cores.[17]

The main pathway for the production of H+
3 is by the reaction of H+
2 and H2.[18]H+
2 + H2 → H+
3 + H

The concentration of H+
2 is what limits the rate of this reaction in nature - the only known natural source of it is via ionization of H2 by a cosmic ray in interstellar space:H2 + cosmic ray → H+
2 + e− + cosmic ray

The cosmic ray has so much energy, it is almost unaffected by the relatively small energy transferred to the hydrogen when ionizing an H2 molecule. In interstellar clouds, cosmic rays leave behind a trail of H+
2, and therefore H+
3. In laboratories, H+
3 is produced by the same mechanism in plasma discharge cells, with the discharge potential providing the energy to ionize the H2.

There are many destruction reactions for H+
3. The dominant destruction pathway in dense interstellar clouds is by proton transfer with a neutral collision partner. The most likely candidate for a destructive collision partner is the second most abundant molecule in space, CO.H+
3 + CO → HCO+ + H2

The significant product of this reaction is HCO+, an important molecule for interstellar chemistry. Its strong dipole and high abundance make it easily detectable by radioastronomy. H+
3 can also react with atomic oxygen to form OH+ and H2.H+
3 + O → OH+ + H2

OH+ then usually reacts with more H2 to create further hydrogenated molecules.OH+ + H2 → OH+
2 + HOH+
2 + H2 → OH+
3 + H

At this point, the reaction between OH+
3 and H2 is no longer exothermic in interstellar clouds. The most common destruction pathway for OH+
3 is dissociative recombination, yielding four possible sets of products: H2O + H, OH + H2, OH + 2H, and O + H2 + H. While water is a possible product of this reaction, it is not a very efficient product. Different experiments have suggested that water is created anywhere from 5–33% of the time. Water formation on grains is still considered the primary source of water in the interstellar medium.

The most common destruction pathway of H+
3 in diffuse interstellar clouds is dissociative recombination. This reaction has multiple products. The major product is dissociation into three hydrogen atoms, which occurs roughly 75% of the time. The minor product is H2 and H, which occurs roughly 25% of the time.
Ortho/Para-H3+[edit]

A collision of ortho-H+
3 and para-H2.

The protons of [1
H
3]+ can be in two different spin configurations, called ortho and para. Ortho-H+
3 has all three proton spins parallel, yielding a total nuclear spin of 3/2. Para-H+
3 has two proton spins parallel while the other is anti-parallel, yielding a total nuclear spin of 1/2.

The most abundant molecule in dense interstellar clouds is 1
H
2 which also has ortho and para states, with total nuclear spins 1 and 0, respectively. When a H+
3 molecule collides with a H2 molecule, a proton transfer can take place. The transfer still yields a H+
3 molecule and a H2 molecule, but can potentially change the total nuclear spin of the two molecules depending on the nuclear spins of the protons. When an ortho-H+
3 and a para-H2 collide, the result may be a para-H+
3 and an ortho-H2.[18]
Spectroscopy[edit]

The spectroscopy of H+
3 is challenging. The pure rotational spectrum is exceedingly weak.[19] Ultraviolet light is too energetic and would dissociate the molecule. Rovibronic(infrared) spectroscopy provides the ability to observe H+
3. Rovibronic spectroscopy is possible with H+
3 because one of the vibrational modes of H+
3, the ν2 asymmetric bend mode, has a weak transition dipole moment. Since Oka's initial spectrum,[6] over 900 absorption lines have been detected in the infrared region. H+
3 emission lines have also been found by observing the atmospheres of the Jovian planets. H+
3 emission lines are found by observing molecular hydrogen and finding a line that cannot be attributed to molecular hydrogen.
Astronomical detection[edit]

H+
3 has been detected in two types of celestial environments: Jovian planets and interstellar clouds. In Jovian planets, it has been detected in the planet's ionospheres, the region where the Sun's high energy radiation ionizes the particles in the atmosphere. Since there is a high level of H2 in these atmospheres, this radiation can produce a significant amount of H+
3. Also, with a broadband source like the Sun, there is plenty of radiation to pump the H+
3 to higher energy states from which it can relax by stimulated and spontaneous emission.
Planetary atmospheres[edit]

The detection of the first H+
3 emission lines was reported in 1989 by Drossart et al.,[7] found in the ionosphere of Jupiter. Drossart found a total of 23 H+
3 lines with a column density of 1.39×109/cm2. Using these lines, they were able to assign a temperature to the H+
3 of around 1,100 K (830 °C), which is comparable to temperatures determined from emission lines of other species like H2. In 1993, H+
3 was found in Saturn by Geballe et al.[8] and in Uranus by Trafton et al.[9]
Molecular interstellar clouds[edit]

H+
3 was not detected in the interstellar medium until 1996, when Geballe & Oka reported the detection of H+
3 in two molecular cloud sightlines, GL2136 and W33A.[12] Both sources had temperatures of H+
3 of about 35 K (−238 °C) and column densities of about 1014/cm2. Since then, H+
3 has been detected in numerous other molecular cloud sightlines, such as AFGL 2136,[20] Mon R2 IRS 3,[20] GCS 3-2,[21] GC IRS 3,[21] and LkHα 101.[22]
Diffuse interstellar clouds[edit]

Unexpectedly, three H+
3 lines were detected in 1998 by McCall et al. in the diffuse cloud sightline of Cyg OB2 No. 12.[13] Before 1998, the density of H2 was thought to be too low to produce a detectable amount of H+
3. McCall detected a temperature of ~27 K (−246 °C) and a column density of ~1014/cm2, the same column density as Geballe & Oka. Since then, H+
3 has been detected in many other diffuse cloud sightlines, such as GCS 3-2,[21] GC IRS 3,[21] and ζ Persei.[23]
Steady-state model predictions[edit]

To approximate the path length of H+
3 in these clouds, Oka[24] used the steady-state model to determine the predicted number densities in diffuse and dense clouds. As explained above, both diffuse and dense clouds have the same formation mechanism for H+
3, but different dominating destruction mechanisms. In dense clouds, proton transfer with CO is the dominating destruction mechanism. This corresponds to a predicted number density of 10−4 cm−3 in dense clouds.n(H+
3) = (ζ / kCO)[n(H2) / n(CO)] ≈ 10−4/cm3n(H+
3) = (ζ / ke)[n(H2) / n(C+)] ≈ 10−6/cm3

In diffuse clouds, the dominating destruction mechanism is dissociative recombination. This corresponds to a predicted number density of 10−6/cm3 in diffuse clouds. Therefore, since column densities for diffuse and dense clouds are roughly the same order of magnitude, diffuse clouds must have a path length 100 times greater than that for dense clouds. Therefore, by using H+
3 as a probe of these clouds, their relative sizes can be determined.
See also[edit]
Dihydrogen cation, H+
2
Helium hydride ion, [HeH]+

https://en.wikipedia.org/wiki/Trihydrogen_cation




his sequence of reactions can be understood by thinking of the two interacting carbon nuclei as coming together to form an excited state of the 24Mg nucleus, which then decays in one of the five ways listed above.[6] The first two reactions are strongly exothermic, as indicated by the large positive energies released, and are the most frequent results of the interaction. The third reaction is strongly endothermic, as indicated by the large negative energy indicating that energy is absorbed rather than emitted. This makes it much less likely, yet still possible in the high-energy environment of carbon burning.[5] But the production of a few neutrons by this reaction is important, since these neutrons can combine with heavy nuclei, present in tiny amounts in most stars, to form even heavier isotopes in the s-process.[7]

The fourth reaction might be expected to be the most common from its large energy release, but in fact it is extremely improbable because it proceeds via electromagnetic interaction,[5] as it produces a gamma ray photon, rather than utilising the strong force between nucleons as do the first two reactions. Nucleons look a lot bigger to each other than they do to photons of this energy. However, the 24Mg produced in this reaction is the only magnesium left in the core when the carbon-burning process ends, as 23Mg is radioactive.

https://en.wikipedia.org/wiki/Carbon-burning_process

NEUTRINO LOSSES

But the main source of neutrinos at these high temperatures involves a process in quantum theory known as pair production. A high energy gamma ray which has a greater energy than the rest mass of two electrons (mass-energy equivalence) can interact with electromagnetic fields of the atomic nuclei in the star, and become a particle and anti-particle pair of an electron and positron.

https://en.wikipedia.org/wiki/Carbon-burning_process

https://en.wikipedia.org/wiki/Carbon-burning_process

In physics, mass–energy equivalence is the relationship between mass and energy in a system's rest frame, where the two values differ only by a constant and the units of measurement.[1][2] The principle is described by the physicist Albert Einstein's famous formula:[3]

https://en.wikipedia.org/wiki/Mass–energy_equivalence

In fluid mechanics, hydrostatic equilibrium (hydrostatic balance, hydrostasy) is the condition of a fluid or plastic solid at rest, which occurs when external forces, such as gravity, are balanced by a pressure-gradient force.[1] In the planetary physics of the Earth, the pressure-gradient force prevents gravity from collapsing the planetary atmosphereinto a thin, dense shell, whereas gravity prevents the pressure-gradient force from diffusing the atmosphere into outer space.[2][3]

Hydrostatic equilibrium is the distinguishing criterion between dwarf planets and small solar system bodies, and features in astrophysics and planetary geology. Said qualification of equilibrium indicates that the shape of the object is symmetrically ellipsoid, where any irregular surface features are consequent to a relatively thin solid crust. In addition to the Sun, there are a dozen or so equilibrium objects confirmed to exist in the Solar System.

https://en.wikipedia.org/wiki/Hydrostatic_equilibrium




A neutrino (/nuːˈtriːnoʊ/ or /njuːˈtriːnoʊ/) (denoted by the Greek letter ν) is a fermion (an elementary particle with spin of 1/2) that interacts only via the weak interaction and gravity.[2][3] The neutrino is so named because it is electrically neutral and because its rest mass is so small (-ino) that it was long thought to be zero. The rest mass of the neutrino is much smaller than that of the other known elementary particles excluding massless particles.[1] The weak force has a very short range, the gravitational interaction is extremely weak, and neutrinos do not participate in the strong interaction.[4] Thus, neutrinos typically pass through normal matter unimpeded and undetected.[2][3]

The first use of a hydrogen bubble chamber to detect neutrinos, on 13 November 1970, at Argonne National Laboratory. Here a neutrino hits a proton in a hydrogen atom; the collision occurs at the point where three tracks emanate on the right of the photograph.

https://en.wikipedia.org/wiki/Neutrino




Carbon detonation or Carbon deflagration is the violent reignition of thermonuclear fusion in a white dwarf star that was previously slowly cooling. It involves a runawaythermonuclear process which spreads through the white dwarf in a matter of seconds, producing a Type Ia supernova which releases an immense amount of energy as the star is blown apart. The carbon detonation/deflagration process leads to a supernova by a different route than the better known Type II (core-collapse) supernova (the type II is caused by the cataclysmic explosion of the outer layers of a massive star as its core implodes).[1]

A white dwarf is the remnant of a small to medium size star (our sun is an example of these). At the end of its life, the star has burned its hydrogen and helium fuel, and thermonuclear fusion processes cease. The star does not have enough mass to either burn much heavier elements, or to implode into a neutron star or type II supernova as a larger star can, from the force of its own gravity, so it gradually shrinks and becomes very dense as it cools, glowing white and then red, for a period many times longer than the present age of the Universe.

https://en.wikipedia.org/wiki/Carbon_detonation




The neon-burning process (nuclear decay) is a set of nuclear fusion reactions that take place in massive stars (at least 8 Solar masses). Neon burning requires high temperatures and densities (around 1.2×109 K or 100 keV and 4×109 kg/m3).

At such high temperatures photodisintegration becomes a significant effect, so some neon nuclei decompose, releasing alpha particles:[1]
20
10Ne
+ γ → 16
8O
+ 4
2He

20
10Ne
+ 4
2He
→ 24
12Mg
+ γ


Alternatively:
20
10Ne
+ n → 21
10Ne
+ γ
21
10Ne
+ 4
2He
→ 24
12Mg
+ n


where the neutron consumed in the first step is regenerated in the second.

https://en.wikipedia.org/wiki/Neon-burning_process




Fission is a form of nuclear transmutation because the resulting fragments (or daughter atoms) are not the same element as the original parent atom. The two (or more) nuclei produced are most often of comparable but slightly different sizes, typically with a mass ratio of products of about 3 to 2, for common fissile isotopes.[3][4] Most fissions are binary fissions (producing two charged fragments), but occasionally (2 to 4 times per 1000 events), three positively charged fragments are produced, in a ternary fission. The smallest of these fragments in ternary processes ranges in size from a proton to an argon nucleus.

https://en.wikipedia.org/wiki/Nuclear_fission

The helium hydride ion or hydridohelium(1+) ion or helonium is a cation (positively charged ion) with chemical formula HeH+. It consists of a helium atom bonded to a hydrogen atom, with one electron removed. It can also be viewed as protonated helium. It is the lightest heteronuclear ion, and is believed to be the first compound formed in the Universe after the Big Bang.[2]

The ion was first produced in a laboratory in 1925. It is stable in isolation, but extremely reactive, and cannot be prepared in bulk, because it would react with any other molecule with which it came into contact. Noted as the strongest known acid, its occurrence in the interstellar medium had been conjectured since the 1970s,[3] and it was finally detected in April 2019 using the airborne SOFIA telescope.[4][5]

https://en.wikipedia.org/wiki/Helium_hydride_ion



The Science

The trihydrogen cation, H3+, is the starting point for almost all molecules in the universe. Typically, H3+ is formed by collisions involving hydrogen gas, but its chemistry at the molecular level is relatively unknown. When organic molecules are hit by a laser pulse, they are ionized and the reaction begins. Then, the molecules break up into different fragments; one of which is H3+. They are able to measure the details of this reaction: the timescales, yield, and how chemical bonds are broken and formed. These experiments also give key details about each step of the reaction which occurs on ultrashort (faster than one millionth of a millionth of a second) timescales.

https://www.energy.gov/science/bes/articles/forming-ion-made-universe

The helium hydride ion or hydridohelium(1+) ion or helonium is a cation (positively charged ion) with chemical formula HeH⁺. It consists of a helium atom bonded to a hydrogen atom, with one electron removed. It can also be viewed as protonated helium. It is the lightest heteronuclear ion, and is believed to be the first compound formed in the Universe after the Big Bang.^[2]

https://en.wikipedia.org/wiki/Helium_hydride_ion

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The dihydrogen cation or hydrogen molecular ion is a cation (positive ion) with formula H+
2. It consists of two hydrogen nuclei (protons) sharing a single electron. It is the simplest molecular ion. 

The ion can be formed from the ionization of a neutral hydrogen molecule H
2. It is commonly formed in molecular clouds in space, by the action of cosmic rays. 

The dihydrogen cation is of great historical and theoretical interest because, having only one electron, the equations of quantum mechanics that describe its structure can be solved in a relatively straightforward way. The first such solution was derived by Ø. Burrau in 1927,^[1] just one year after the wave theory of quantum mechanics was published

Isotopologues[edit]

The dihydrogen cation has six isotopologues, that result from replacement of one or more protons by nuclei of the other hydrogen isotopes; namely, deuterium nuclei (deuterons, 2
H⁺) or tritium nuclei (tritons, 3
H⁺).^[4][5]

• H+
  2 = 1
  H+
  2 (the common one). ^[4][5]
• [DH]⁺ = [2
  H1
  H]⁺ (deuterium hydrogen cation). ^[4]
• D+
  2 = 2
  H+
  2 (dideuterium cation). ^[4][5]
• [TH]⁺ = [3
  H1
  H]⁺ (tritium hydrogen cation).
• [TD]⁺ = [3
  H2
  H]⁺ (tritium deuterium cation).
• T+
  2 = 3
  H+
  2 (ditritium cation). ^[5]

The dihydrogen ion is formed in nature by the interaction of cosmic rays and the hydrogen molecule. An electron is knocked off leaving the cation behind.^[17]

H₂ + cosmic ray → H+
2 + e⁻ + cosmic ray.

Cosmic ray particles have enough energy to ionize many molecules before coming to a stop.

The ionization energy of the hydrogen molecule is 15.603 eV. High speed electrons also cause ionization of hydrogen molecules with a peak cross section around 50 eV. The peak cross section for ionization for high speed protons is 70000 eV with a cross section of 2.5×10⁻¹⁶ cm². A cosmic ray proton at lower energy can also strip an electron off a neutral hydrogen molecule to form a neutral hydrogen atom and the dihydrogen cation, (p⁺ + H₂ → H + H+
2) with a peak cross section at around 8000 eV of 8×10⁻¹⁶ cm².^[18]

An artificial plasma discharge cell can also produce the ion.^{[citation needed]}

In nature the ion is destroyed by reacting with other hydrogen molecules:

H+
2 + H₂ → H+
3 + H.

https://en.wikipedia.org/wiki/Dihydrogen_cation

https://en.wikipedia.org/wiki/Dihydrogen_cation

Triatomic hydrogen or H₃ is an unstable triatomic molecule containing only hydrogen. Since this molecule contains only three atoms of hydrogen it is the simplest triatomic molecule^[1] and it is relatively simple to numerically solve the quantum mechanics description of the particles. Being unstable the molecule breaks up in under a millionth of a second. Its fleeting lifetime makes it rare, but it is quite commonly formed and destroyed in the universe thanks to the commonness of the trihydrogen cation. The infrared spectrum of H₃ due to vibration and rotation is very similar to that of the ion, H+
3. In the early universe this ability to emit infrared light allowed the primordial hydrogen and helium gas to cool down so as to form stars.

Formation[edit]

The neutral molecule can be formed in a low pressure gas discharge tube.^[2]

A neutral beam of H₃ can be formed from a beam of H+
3 ions passing through gaseous potassium, which donates an electron to the ion, forming K⁺.^[3] Other gaseous alkali metals, such as caesium, can also be used to donate electrons.^[4] H+
3 ions can be made in a duoplasmatron where an electric discharge passed through low pressure molecular hydrogen. This causes some H₂ to become H+
2. Then H₂ + H+
2 → H+
3 + H. The reaction is exothermic with an energy of 1.7 eV, so the ions produced are hot with much vibrational energy. These can cool down via collisions with cooler gas if the pressure is high enough. This is significant because strongly vibrating ions produce strongly vibrating neutral molecules when neutralised according to the Franck–Condon principle.^[3]

Breakup[edit]

H₃ can break up in the following ways:

 ^[5]

https://en.wikipedia.org/wiki/Triatomic_hydrogen

The Duoplasmatron is an ion source in which a cathode filament emits electrons into a vacuum chamber.^[1] A gas such as argon is introduced in very small quantities into the chamber, where it becomes charged or ionized through interactions with the free electrons from the cathode, forming a plasma. The plasma is then accelerated through a series of at least two highly charged grids, and becomes an ion beam, moving at fairly high speed from the aperture of the device.

https://en.wikipedia.org/wiki/Duoplasmatron

The trihydrogen cation or protonated molecular hydrogen is a cation (positive ion) with formula H+
3, consisting of three hydrogen nuclei (protons) sharing two electrons.

The trihydrogen cation is one of the most abundant ions in the universe. It is stable in the interstellar medium (ISM) due to the low temperature and low density of interstellar space. The role that H+
3 plays in the gas-phase chemistry of the ISM is unparalleled by any other molecular ion.

The trihydrogen cation is the simplest triatomic molecule, because its two electrons are the only valence electrons in the system. It is also the simplest example of a three-center two-electron bond system.

https://en.wikipedia.org/wiki/Trihydrogen_cation

The Duoplasmatron is an ion source in which a cathode filament emits electrons into a vacuum chamber.^[1] A gas such as argon is introduced in very small quantities into the chamber, where it becomes charged or ionized through interactions with the free electrons from the cathode, forming a plasma. The plasma is then accelerated through a series of at least two highly charged grids, and becomes an ion beam, moving at fairly high speed from the aperture of the device.

https://en.wikipedia.org/wiki/Duoplasmatron

The shape of the molecule is predicted to be an equilateral triangle.^[1] Vibrations can occur in the molecule in two ways, firstly the molecule can expand and contract retaining the equilateral triangle shape (breathing), or one atom can move relative to the others distorting the triangle (bending). The bending vibration has a dipole moment and thus couples to infrared radiation.^[1]

https://en.wikipedia.org/wiki/Triatomic_hydrogen

Gerhard Herzberg was the first to find spectroscopic lines of neutral H₃ when he was 75 years old in 1979. Later he announced that this observation was one of his favourite discoveries.^[8] The lines came about from a cathode discharge tube.^[8] The reason that earlier observers could not see any H₃ spectral lines, was due to them being swamped by the spectrum of the much more abundant H₂. The important advance was to separate out H₃ so it could be observed alone. Separation uses mass spectroscopy separation of the positive ions, so that H₃ with mass 3 can be separated from H₂ with mass 2. However there is still some contamination from HD, which also has mass 3.^[3] The spectrum of H₃ is mainly due to transitions to the longer lived state of 2p²A₂". The spectrum can be measured via a two step photo-ionization method.^[1]

https://en.wikipedia.org/wiki/Triatomic_hydrogen

Dark matter is a hypothetical form of matter thought to account for approximately 85% of the matter in the universe and about 27% of its total mass–energy density^[1] or about 2.241×10⁻²⁷ kg/m³. Its presence is implied in a variety of astrophysicalobservations, including gravitational effects that cannot be explained by accepted theories of gravity unless more matter is present than can be seen. For this reason, most experts think that dark matter is abundant in the universe and that it has had a strong influence on its structure and evolution. Dark matter is called dark because it does not appear to interact with the electromagnetic field, which means it does not absorb, reflect or emit electromagnetic radiation, and is therefore difficult to detect.^[2]

https://en.wikipedia.org/wiki/Dark_matter

In the fields of Big Bang theory and cosmology, reionization is the process that caused matter in the universe to reionize after the lapse of the "dark ages".

Reionization is the second of two major phase transitions of gas in the universe^{[citation needed]} (the first is recombination). While the majority of baryonic matter in the universe is in the form of hydrogen and helium, reionization usually refers strictly to the reionization of hydrogen, the element.

It is believed that the primordial helium also experienced the same phase of reionization changes, but at different points in the history of the universe. This is usually referred to as helium reionization.

The first phase change of hydrogen in the universe was recombination, which occurred at a redshift z = 1089 (379,000 years after the Big Bang), due to the cooling of the universe to the point where the rate of recombination of electrons and protons to form neutral hydrogen was higher than the reionization rate.^{[citation needed]} The universe was opaque before the recombination, due to the scattering of photons (of all wavelengths) off free electrons (and, to a significantly lesser extent, free protons), but it became increasingly transparent as more electrons and protons combined to form neutral hydrogen atoms. While the electrons of neutral hydrogen can absorb photons of some wavelengths by rising to an excited state, a universe full of neutral hydrogen will be relatively opaque only at those absorbed wavelengths, but transparent throughout most of the spectrum. The Dark Ages of the universe start at that point, because there were no light sources other than the gradually redshifting cosmic background radiation.

The second phase change occurred once objects started to condense in the early universe that were energetic enough to re-ionize neutral hydrogen. As these objects formed and radiated energy, the universe reverted from being composed of neutral atoms, to once again being an ionized plasma. This occurred between 150 million and one billion years after the Big Bang (at a redshift 6 < z < 20).^{[citation needed]} At that time, however, matter had been diffused by the expansion of the universe, and the scattering interactions of photons and electrons were much less frequent than before electron-proton recombination. Thus, the universe was full of low density ionized hydrogen and remained transparent, as is the case today.

https://en.wikipedia.org/wiki/Reionization

Cation[edit]

The related H+
3 ion is the most prevalent molecular ion in interstellar space. It is believed to have played a crucial role in the cooling of early stars in the history of the Universe through its ability readily to absorb and emit photons.^[9] One of the most important chemical reactions in interstellar space is H+
3 + e⁻ → H₃ and then → H₂ + H.^[6]

J. J. Thomson observed H+
3 while experimenting with positive rays. He believed that it was an ionised form of H₃ from about 1911. He believed that H₃ was a stable molecule and wrote and lectured about it. He stated that the easiest way to make it was to target potassium hydroxide with cathode rays.^[8] In 1913 Johannes Stark proposed that three hydrogen nuclei and electrons could form a stable ring shape. In 1919 Niels Bohr proposed a structure with three nuclei in a straight line, with three electrons orbiting in a circle around the central nucleus. He believed that H+
3 would be unstable, but that reacting H−
2 with H⁺ could yield neutral H₃.  Stanley Allen's structure was in the shape of a hexagon with alternating electrons and nuclei.^[8]

https://en.wikipedia.org/wiki/Triatomic_hydrogen

Cyclic ozone is a theoretically predicted form of ozone. Like ordinary ozone (O₃), it would have three oxygen atoms. It would differ from ordinary ozone in how those three oxygen atoms are arranged. In ordinary ozone, the atoms are arranged in a bent line; in cyclic ozone, they would form an equilateral triangle.

https://en.wikipedia.org/wiki/Cyclic_ozone#cite_note-sciencedaily-4

Helium Hydride Ion 

The ion was first produced in a laboratory in 1925. It is stable in isolation, but extremely reactive, and cannot be prepared in bulk, because it would react with any other molecule with which it came into contact. Noted as the strongest known acid, its occurrence in the interstellar medium had been conjectured since the 1970s,^[3] and it was finally detected in April 2019 using the airborne SOFIA telescope.^[4][5]

https://en.wikipedia.org/wiki/Helium_hydride_ion