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Topic: Molecular hydrogen

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	Molecular Attraction: Hydrogen Bonding
		Hydrogen bonding is the strongest of the forces between molecules that have no formal charge.
		Since the hydrogens are connected to highly electronegative atoms, their electron density is pulled away from them.
		Hydrogen bonds are essentially just the mother of all dipole interactions: in other words, the dipole interaction between a partially positive hydrogen attached to an oxygen atom with that of another oxygen atom is large enough to warrant its own special classification, as a hydrogen bond.
	www.chemhelper.com /molatt2.html (287 words)

	Atomic Hydrogen-Molecular Hydrogen-Nascent Hydrogen-atomic hydrogen torch-energy by hydrogen
		Hydrogen obtained by the dissociation of molecular hydrogen is called atomic hydrogen.
		When molecular hydrogen is passed through an electric discharge, which is set up between two electrodes, it dissociated into atomic hydrogen.
		Hydrogen gas liberated during a chemical reaction is always in atomic state, which is known as nascent hydrogen.
	www.citycollegiate.com /atomichydrogen.htm (250 words)

	hydrogen
		Hydrogen is the most abundant of all elements in the universe, and it is thought that the heavier elements were, and still are, being built from hydrogen and helium.
		It is thought that hydrogen is a major component of the planet Jupiter and that at some depth in the planet's interior the pressure is so great that solid molecular hydrogen is converted into solid metallic hydrogen.
		On earth, hydrogen occurs chiefly in combination with oxygen in water, but it is also present in organic matter such as living plants, petroleum, coal, etc. It is present as the free element in the atmosphere, but only to the extent of less than 1 ppm by volume.
	www.speclab.com /elements/hydrogen.htm (901 words)

	Discovery of H2 in Space Explains Dark Matter and Redshift
		Yet it is a well-known fact of basic chemistry that atomic hydrogen is extremely unstable, and that it reacts violently to produce molecular hydrogen, which is extremely stable.
		Because atomic and molecular hydrogen have an approximately homogenous distribution in the universe, this induces a non-Doppler redshift, which is proportional to the distance of the light source (just as for an apparently expanding universe, assumed with a Doppler interpretation).
		That molecular hydrogen is responsible for the redshift which is erroneously believed to have a cosmological Doppler origin.
	www.newtonphysics.on.ca /hydrogen/index.html (2101 words)

	Molecular Hydrogen Discovery Aids Researchers
		Molecular hydrogen, composed of two hydrogen atoms, is important because it fuels starbirth, Shull said.
		Stars form in dark, cold regions of space called molecular clouds, which scientists have long assumed are packed with molecular hydrogen.
		According to one calculation, based on previous assumptions of the amount of molecular hydrogen in the galaxy, all the gas would be used up in 250 million years.
	casa.colorado.edu /TourofCASA/InTheMedia/dcamera_113_2000.shtml (394 words)

	The Birth of Stars
		A high concentration of molecular hydrogen and dust causes the molecular cloud to absorb all light from the stars behind it.
		Molecular clouds, which are the origination of many stars, are very difficult to study because they are primarily composed of molecular hydrogen at temperatures only about 10 degrees above absolute zero.
		Since hydrogen is virtually invisible under those conditions with normal detection methods, 99% or more of a molecular cloud cannot be seen with standard methods.
	csep10.phys.utk.edu /astr162/lect/birth/birth.html (527 words)

	Hydrogen - Wikipedia, the free encyclopedia
		Hydrogen (IPA: /ˈhʌɪdrə(ʊ)dʒən/, Latin: 'hydrogenium', from Ancient Greek: hydro: "water" and genes: "forming") is a chemical element in the periodic table that has the symbol H and atomic number 1.
		Hydrogen solubility in metals is influenced by local distortions or impurities in the metal crystal lattice.
		Spectroscopy of superheavy hydrogen isotopes in stopped-pion absorption by nuclei.
	en.wikipedia.org /wiki/Molecular_hydrogen (3993 words)

	ScienceDaily: Astronomers Find Molecular Hydrogen At Edge Of Universe
		Using a quasar located 12.3 billion light-years away as a beacon, a team of astronomers detected the presence of molecular hydrogen in the farthest system ever, an otherwise invisible galaxy that we observe when the Universe was less than 1.5 billion years old, that is, about 10% of its present age.
		"Detecting molecular hydrogen and measuring its properties in the most remote parts of the Universe is important to understand the gas environment and determine the rate of star formation in the early Universe", said Cédric Ledoux, lead-author of the paper presenting the results.
		In particular, many lines from molecular hydrogen were found, breaking the record for the detection of this element in the farthest object in the Universe.
	www.sciencedaily.com /releases/2006/05/060508112217.htm (2102 words)

	Columns:: Power supply: Study demonstrates that bacterial pathogens use molecular hydrogen as an energy source in ...
		Tests have shown the presence of hydrogen in the breath of human test subjects, indicating it is somewhere in the body, but scientists were virtually unanimous in believing that any molecular hydrogen produced in the body was excreted as an unneeded waste product, with no role in metabolism or cell growth.
		Maier resolved to find out once and for all where such hydrogen might be, so he inserted a tiny probe into the stomachs of living mice and measured the amounts of hydrogen in the area of the animals’ mucosal layer.
		Hydrogen levels have recently been measured in the termite hind-gut and in the cockroach mid-gut, but this is the first evidence of it within vertebrate tissue.
	www.uga.edu /columns/030121/news7.html (1026 words)

	MOLECULAR HYDROGEN AND WATER VAPOUR EMISSIONS IN A GLOBAL HYDROGEN ENERGY ECONOMY
		Hydrogen can play a major role in such an economy whereever its qualities are needed: it is mobile and can replace oil as fuel for vehicle and aircraft, it is gaseous and can be transported and distributed in pipelines instead of natural gas.
		It is the aim of this article to sketch the emissions of water vapour and hydrogen from a global hydrogen energy economy in the context of total hydrogen and water balances.
		Hydrogen emissions of a future energy economy - when assuming 2 to 3 percent losses into the atmosphere - would be in the same range as those of present day hydrogen emissions from uncomplete fossil fuel combustion (under the assumption that half of the present energy supply would be covered by hydrogen).
	www.hydrogen.org /Wissen/Vapour.htm (2751 words)

	Discovery of H2 in Space Explains Dark Matter and Redshift
		Although hydrogen in the atomic form is easily detected through radioastronomy, the molecular form is difficult to detect.
		This is not the case, because non-ionized atomic hydrogen is observed, even though it requires less energy to ionize the atomic than the molecular form of hydrogen.
		Since a much larger amount of molecular hydrogen than previously admitted has been observed in the universe, we can now see how this hydrogen is responsible for the redshift observed.
	home.pacbell.net /skeptica/pc.html (2197 words)

	index
		"Detecting molecular hydrogen and measuring its properties in the most remote parts of the Universe is important to understand the gas environment and determine the rate of star formation in the early Universe", said Cédric Ledoux, lead-author of the paper presenting the results [1].
		A similar set of accurate measurements of molecular hydrogen lines was made by the astronomers [4] with UVES on the VLT towards two others quasars, Q 0405-443 and Q 0347-383.
		This set of data allowed the scientists to compare the ratio of the mass of a proton to that of an electron in molecular hydrogen as it is now and how it was about 12 billion years ago [5].
	www.eso.org /outreach/press-rel/pr-2006/pr-16-06.html (1174 words)

	Empirical and Molecular Formula
		The empirical formula for a compound is the simplest formula that shows the ratio of the numbers of atoms of each kind in the compound, e.g.
		Therefore, the molecular formula of a compound is the multiples of empirical formula, e.g.
		By entering the percentages or the mass of elements in a compound and the weight of it, optionally, the module calculates the empirical formula/weight and molecular formula/weight if the molecular weight is given.
	www.molecularsoft.com /data/help/formula.htm (227 words)

	USATODAY.com - Sun may help produce hydrogen fuel someday (Site not responding. Last check: 2007-10-13)
		The research unveils fundamental information about the chemistry that prepares molecular hydrogen to be burned as fuel, opening new doors for development.
		These early molecular catalysts produced one molecule of hydrogen for every molecule of compound, bit by bit.
		Phasing in hydrogen as a fuel on a greater scale serves humanity, Nocera emphasizes.
	www.usatoday.com /news/science/aaas/2001-08-30-hydrogen-advances.htm (888 words)

	Observations and Modeling of the Atmospheric Molecular Hydrogen Cycle II Posters - Atmospheric Sciences [A]
		The isotopic composition of hydrogen produced by photo-oxidation of methane, $\delta$D$_{h }$$_{\nu}$, is an important and at present poorly constrained term in the global isotope budget of H$_{2}$.
		While it is well known that the byproduct of energy produced from hydrogen is water vapor, it is not well known that the storage and transfer of hydrogen is inevitably accompanied by measurable leakage of hydrogen.
		Data for hydrogen consumption from on-road vehicles was derived from the number of miles driven in each U.S. county based on 1999 NEI data, the average fleet mileage of all on-road vehicles, the average gasoline vehicle efficiency, and the efficiency of advanced 2004 fuel cell vehicles.
	www.agu.org /meetings/fm04/fm04-sessions/fm04_A31B.html (3214 words)

	Universe Today - Bumpy Dust Makes Molecular Hydrogen
		They've developed a simulation that shows how molecular hydrogen is more likely to form on interstellar grains of dust which are bumpy, and not smooth.
		When they peer through their telescopes, they see hydrogen in the vast clouds of dust and gas between stars —- especially in the denser regions that are collapsing to form new stars and planets.
		For two hydrogen atoms to have enough energy to bond in the cold reaches of space, they first have to meet on a surface, explained Eric Herbst, Distinguished University Professor of physics at Ohio State.
	www.universetoday.com /am/publish/bumpy_dust_hydrogen.html?2362005 (711 words)

	Introduction to Molecular Orbital Theory
		With a hydrogen atom the probability distribution is spherical around the nucleus and it is possible to draw a spherical boundary surface, inside which there is a 95% possibility of finding the electron.
		There are two molecular orbitals for hydrogen, the lower energy orbital has its greater electron density between the two nuclei.
		The upper molecular orbital has a node in the electronic wave function and the electron density is low between the two positively charged nuclei.
	www.ch.ic.ac.uk /vchemlib/course/mo_theory/main.html (2412 words)

	Spaceflight Now \| Breaking News \| 'Bumpy space dust' explains most common molecule
		When they peer through their telescopes, they see hydrogen in the vast clouds of dust and gas between stars -- especially in the denser regions that are collapsing to form new stars and planets.
		Hydrogen is the simplest atomic element known; it consists of just one proton and one electron.
		When it comes to making molecular hydrogen, the ideal microscopic host surface is "less like the flatness of Ohio and more like a Manhattan skyline," Herbst said.
	www.spaceflightnow.com /news/n0506/23molecule (909 words)

	Observations and Modeling of the Atmospheric Molecular Hydrogen Cycle I - Atmospheric Sciences [A]
		The potential of hydrogen leaks from implementation of a global hydrogen economy and the impacts related to depletion of stratospheric ozone have been recently discussed in the scientific literature.
		We discuss the deuterium flow among the long-lived hydrogen compounds, CH$_{4}$, H$_{2}$, and H$_{2}$O in the stratosphere and mesosphere based on the recent observations of the mixing ratios and isotopic ratios of H$_{2}$ and CH$_{4}$ in the stratosphere.
		Hydrogen uptake in soil is the largest single component of the global budget of atmospheric H2, and is the most important parameter for predicting changes in atmospheric concentration with future changing sources (anthropogenic and otherwise).
	www.agu.org /meetings/fm04/fm04-sessions/fm04_A23E.html (2703 words)

	SPACE.com -- Solar Systems Like Ours May Be Common, Study Shows
		Ivison said much of the missing matter must still be what is known as dark matter, according to current theories, and could not be accounted for by molecular hydrogen.
		Hydrogen is by far the most abundant element in the universe.
		Previous studies of the three nearby stars had measured carbon monoxide, using that as an indicator of how much molecular hydrogen was present.
	www.space.com /scienceastronomy/astronomy/gas_giants_000104-2.html (556 words)

	Interstellar Medium and the Milky Way
		The hydrogen gas is observed in a variety of states: in ionized, neutral atomic, and molecular forms.
		The ionized hydrogen emits light in the visible band as the electrons recombine with the protons and the neutral atomic and molecular hydrogen emits light in the radio band of the electromagnetic spectrum.
		Not much molecular gas is located at 4,900 to 9,800 light years from center but about 15% of the total molecular gas mass is located close to galactic center within 4,900 light years from the center.
	www.astronomynotes.com /ismnotes/s3.htm (2498 words)

	molecular hydrogen concept from the Astronomy knowledge base (Site not responding. Last check: 2007-10-13)
		None of its transitions lie in the visible part of the spectrum.
		ortho-hydrogen (2 facts) - Molecular hydrogen in which the two protons of the diatomic molecule have the same direction of spin.
		para-hydrogen (2 facts) - Molecular hydrogen in which the two protons of the diatomic molecule have opposite directions of spin.
	www.site.uottawa.ca:4321 /astronomy/molecularhydrogen.html (247 words)

	Press Release for Nature Molecular Hydrogen Article
		, two hydrogen atoms joined together by a molecular bond, dominates the primordial matter from which stars and planets are made, only about 1% by mass is present as dust or ice.
		Though much of the hydrogen is lost as planetary systems are born, the solids coagulate and settle under the influence of gravity, eventually forming into asteroids, comets, and, finally, planets.
		The 12 µm thermal emission measurement of HD 135344 was acquired with the LWS camera at the Keck I telescope by G. Blake and J. Kessler.
	www.gps.caltech.edu /~gab/press/h2_press.html (940 words)

	Molecular hydrogen found at universe edge
		The hydrogen was observed in the farthest system ever seen -- an otherwise invisible galaxy that is observed as it was when the universe was less than 1.5 billion years old, about 10 percent of its present age.
		Although molecular hydrogen is the most abundant molecule in the universe, it is very difficult to detect directly.
		For the time being, the only way to detect it in the far universe is to search for its telltale signatures in the spectra of quasars or gamma-ray burst afterglows.
	www.softcom.net /webnews/wed/cg/Ueurope-hydrogen.Rivh_Gy9.html (206 words)

	Molecular Hydrogen in Space - Cambridge University Press (Site not responding. Last check: 2007-10-13)
		Molecular hydrogen is the most abundant molecule in the Universe.
		In recent years, advances in theory and laboratory experiments coupled with breakthrough observations with important new telescopes and satellites have revolutionized our understanding of molecular hydrogen in space.
		It is now possible to address the question of how molecular hydrogen formed in the early Universe and the role it played in the formation of primordial structures.
	www.cambridge.org /catalogue/catalogue.asp?isbn=0521782244 (359 words)

	Biohydrogen Generation - GCEP
		The long term goal for this project is to develop efficient and economical technology for the biological conversion of solar energy into molecular hydrogen.
		Thus, the initial focus of this part of the project is to establish protein evolution methods capable of evolving a highly active hydrogenase (such as the one from Clostridium pasteurianum) to be insensitive to inactivation by molecular oxygen.
		Based on the 3-D structure and the molecular properties of the Fe-S hydrogenase (CpI) from Clostridium pasteurianum, this enzyme will be modified to become oxygen tolerant.
	gcep.stanford.edu /research/factsheets/biohydrogen_generation.html (742 words)

	Los Alamos researchers measure atmospheric isotope buildup
		Deuterium levels in molecular hydrogen act as a fingerprint of the deuterium source.
		In addition, in the troposphere, the lowest level of Earth’s atmosphere, increased molecular hydrogen could reduce the amount of hydroxyl radicals — chemicals that are available to help scrub greenhouse gases such as methane from the atmosphere.
		Continuous measurements of atmospheric hydrogen and deuterium are needed to establish a baseline in anticipation of a transition to a hydrogen economy, an area that Los Alamos is keenly interested in pursuing.
	www.lanl.gov /worldview/news/releases/archive/03-113.shtml (913 words)

	New Molecular Hydrogen Outflow in Serpens
		= 3, the extinction to the Serpens molecular cloud (Eiroa and Casali 1992, hereafter EC92).
		Note that the molecular hydrogen outflow powering Burnham's Nebula displays similar velocity and brightness variations (Herbst, Robberto, and Beckwith 1997).
		Finally, both CK-8 (EC92) and the molecular hydrogen (§ 3.1) appear to suffer 3 mag of visual extinction, suggesting they lie at a similar distance along the line of sight into the cloud.
	ecf.hq.eso.org /~ralbrech/sepdec97apjl/5232.html (2394 words)

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