These are organized by a classification scheme developed exclusively for Cosma. More…
molecule : the smallest particle of a substance that retains all the properties of the substance and is composed of one or more atoms — Webster
Molecule is an electrically neutral group of two or more atoms held together by chemical bonds. A molecule may be homonuclear, that is, it consists of atoms of one chemical element, as with oxygen (O2); or it may be heteronuclear, a chemical compound composed of more than one element, as with water (H2O). Atoms and complexes connected by non-covalent interactions, such as hydrogen bonds or ionic bonds, are generally not considered single molecules.
Molecules as components of matter are common in organic substances (and therefore biochemistry). They also make up most of the oceans and atmosphere. However, the majority of familiar solid substances on Earth, including most of the minerals that make up the crust, mantle, and core of the Earth, contain many chemical bonds, but are not made of identifiable molecules. Also, no typical molecule can be defined for ionic crystals (salts) and covalent crystals (network solids), although these are often composed of repeating unit cells that extend either in a plane (such as in graphene) or three-dimensionally (such as in diamond, quartz, or sodium chloride). The theme of repeated unit-cellular-structure also holds for most condensed phases with metallic bonding, which means that solid metals are also not made of molecules. In glasses (solids that exist in a vitreous disordered state), atoms may also be held together by chemical bonds with no presence of any definable molecule, nor any of the regularity of repeating units that characterizes crystals. — Wikipedia
Molecular physics is the study of the physical properties of molecules, the chemical bonds between atoms as well as the molecular dynamics. Its most important experimental techniques are the various types of spectroscopy; scattering is also used. The field is closely related to atomic physics and overlaps greatly with theoretical chemistry, physical chemistry and chemical physics.
In addition to the electronic excitation states which are known from atoms, molecules exhibit rotational and vibrational modes whose energy levels are quantized. The smallest energy differences exist between different rotational states: pure rotational spectra are in the far infrared region (about 30 – 150 µm wavelength) of the electromagnetic spectrum. Vibrational spectra are in the near infrared (about 1 – 5 µm) and spectra resulting from electronic transitions are mostly in the visible and ultraviolet regions. From measuring rotational and vibrational spectra properties of molecules like the distance between the nuclei can be specifically calculated.
One important aspect of molecular physics is that the essential atomic orbital theory in the field of atomic physics expands to the molecular orbital theory. — Wikipedia
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Clearest view ever of cell membrane yields...
on December 12, 2018 at 5:51 pm
Working with a Nobel Prize-winning biophysicist, a team of researchers at Virginia Commonwealth University has gained the clearest view yet of a patch of cell membrane and its components, revealing unexpected structures and opening up new possibilities for pharmaceutical research. […]
Seeing small-molecule interactions inside cells
on December 12, 2018 at 5:04 pm
Like people in a large company, proteins in cells constantly interact with each other to perform various jobs. To develop new disease therapies, researchers are trying to control these interactions with small-molecule drugs that cause specific proteins to associate more or less with their "coworkers." Now, researchers reporting in ACS' journal Analytical Chemistry have developed a method to visualize whether drugs are regulating protein-protein interactions inside cells. […]
Researchers reverse engineer way pine trees...
on December 12, 2018 at 3:31 pm
Washington State University researchers have reverse engineered the way a pine tree produces a resin, which could serve as an environmentally friendly alternative to a range of fossil-fuel based products worth billions of dollars. […]
Research unlocks secrets of iron storage in algae
on December 12, 2018 at 3:22 pm
New research shows that phytoplankton iron storage strategies may determine which species thrive in changing oceans and impact marine food webs, according to a recent paper in the Proceedings of the National Academy of Sciences. The research examined two primary methods of iron storage and found that one makes species more resilient against shortages of the rare and essential element. […]
Obtaining polyester from plant oil
on December 12, 2018 at 3:18 pm
The development of future technologies that are not based on mineral oil and can be used for producing chemicals and plastics is one of the major tasks in modern materials science and a key challenge that needs to be addressed if sustainable industrial production is to have a future. A range of theoretical concepts and laboratory processes must be devised and tested to resolve challenges and problems arising in connection with the natural materials before potential applications for materials […]