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Hydrogen Bonds

Hydrogen Bonds

Hydrogen BondsHydrogen bonds are weak attractions between atoms that have formed other chemical bonds. One of these atoms is electronegative, like oxygen, and has a partial negative charge. The other is a hydrogen atom that has bonded with another electronegative atom and has a partial positive charge.Hydrogen Bonds Control the World!Because hydrogen has very weak electronegativity when it binds with a strongly electronegative atom, such as oxygen or nitrogen, electrons in the bond are...

Hydrogen Bonds

Hydrogen Bonds

A hydrogen bond is formed when a weakly positive hydrogen atom already bonded to one electronegative atom (for example, the oxygen in the water molecule) is attracted to another electronegative atom from another polar molecule, such as water (H2O), hydrogen fluoride (HF), or ammonia (NH3). The huge electronegativity difference between the H atom (2.1) and the atom to which it is bonded (4.0 for an F atom, 3.5 for an O atom, or 3.0 for an N atom), combined with the very small size of an H atom...

Nuclear Fusion

Nuclear Fusion

The process of converting very light nuclei into heavier nuclei is also accompanied by the conversion of mass into large amounts of energy, a process called fusion. The principal source of energy in the sun is a net fusion reaction in which four hydrogen nuclei fuse and ultimately produce one helium nucleus and two positrons.
A helium nucleus has a mass that is 0.7% less than that of four hydrogen nuclei; this lost mass is converted into energy during the fusion. This reaction produces about...

Gravitation Between Spherically Symmetric Masses

Gravitation Between Spherically Symmetric Masses

The gravitational potential energy between two spherically symmetric bodies can be calculated from the masses and the distance between the bodies, assuming that the center of mass is concentrated at the respective centers of the bodies.

Detection of Black Holes

Detection of Black Holes

Although black holes were theoretically postulated in the 1920s, they remained outside the domain of observational astronomy until the 1970s.
Their closest cousins are neutron stars, which are composed almost entirely of neutrons packed against each other, making them extremely dense. A neutron star has the same mass as the Sun but its diameter is only a few kilometers. Therefore, the escape velocity from their surface is close to the speed of light.
Not until the 1960s, when the first neutron...

Intermolecular Forces

Intermolecular Forces

Atoms and molecules interact through bonds (or forces): intramolecular and intermolecular. The forces are electrostatic as they arise from interactions (attractive or repulsive) between charged species (permanent, partial, or temporary charges) and exist with varying strengths between ions, polar, nonpolar, and neutral molecules. The different types of intermolecular forces are ion–dipole, dipole–dipole, hydrogen bonds, and dispersion; among these, dipole–dipole, hydrogen bonds, and dispersion...

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Related Experiment Video

Updated: Jul 12, 2026

Quantification of Hydrogen Concentrations in Surface and Interface Layers and Bulk Materials through Depth Profiling with Nuclear Reaction Analysis

Quantification of Hydrogen Concentrations in Surface and Interface Layers and Bulk Materials through Depth Profiling with Nuclear Reaction Analysis

Published on: March 29, 2016

Search for interstellar superheavy hydrogen.

M Jura, D G York

Science (New York, N.Y.)

|April 2, 1982

Summary

Astronomers searched for superheavy particles (X+) mimicking neutral hydrogen in stellar spectra. An upper limit was set for X+ abundance, finding it extremely rare in the interstellar medium.

Area of Science:

* Particle Physics and Astrophysics
* Cosmic Abundance Studies

Background:

* Theoretical models predict stable, superheavy elementary particles beyond the proton mass.
* Such particles, if positively charged (X+), could form neutral atoms with electrons.
* These superheavy hydrogen analogs could exist in the interstellar medium.

Purpose of the Study:

* To search for evidence of superheavy particles (X+) in astronomical observations.
* To constrain the cosmic abundance of hypothetical superheavy particles.

Main Methods:

* Analysis of stellar spectra, specifically targeting the spectral signature of superheavy neutral hydrogen.
* Observation of the line of sight toward the bright star gamma Cassiopeiae.

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Related Experiment Videos

Last Updated: Jul 12, 2026

Quantification of Hydrogen Concentrations in Surface and Interface Layers and Bulk Materials through Depth Profiling with Nuclear Reaction Analysis

Quantification of Hydrogen Concentrations in Surface and Interface Layers and Bulk Materials through Depth Profiling with Nuclear Reaction Analysis

Published on: March 29, 2016

Cryogenic Liquid Jets for High Repetition Rate Discovery Science

Cryogenic Liquid Jets for High Repetition Rate Discovery Science

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Supercritical Nitrogen Processing for the Purification of Reactive Porous Materials

Supercritical Nitrogen Processing for the Purification of Reactive Porous Materials

Published on: May 15, 2015

Main Results:

* No definitive evidence for the superheavy particle X+ was found.
* An upper limit for the relative abundance of X+ to normal hydrogen was established at 2 x 10(-8).

Conclusions:

* The cosmic abundance of the searched-for superheavy particle X+ is highly constrained.
* The findings place limits on certain particle physics models predicting such particles.