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
Phys.org - latest science and technology news stories Phys.org internet news portal provides the latest news on science including: Physics, Nanotechnology, Life Sciences, Space Science, Earth Science, Environment, Health and Medicine.
- Key protein linked to appetite and obesity in miceon October 15, 2021 at 5:34 pm
Researchers from the Okinawa Institute of Science and Technology Graduate University (OIST) have identified a protein that plays a key role in how the brain regulates appetite and metabolism. Loss of the protein, XRN1, from the forebrain, resulted in obese mice with an insatiable appetite, according to a new study published in the journal, iScience.
- How herpes seizes proteins' means of productionon October 15, 2021 at 2:52 pm
The Graham and Crump groups at the University of Cambridge and the Svergun Group at EMBL Hamburg have discovered a mechanism by which the herpes simplex virus takes control of the molecular machinery of human cells. Their work reveals how a dedicated viral protein hijacks key host proteins, forcing the host cell to produce and release copies of the virus.
- Synthetic biology moves into the realm of the...on October 15, 2021 at 1:45 pm
The field of synthetic biology has had great success engineering yeast and bacteria to make chemicals—biofuels, pharmaceuticals, fragrances, even the hoppy flavors of beer—cheaply and more sustainably, with only sugar as the energy source.
- Making progress towards quantum technologies...on October 15, 2021 at 1:45 pm
An international research team, with the participation of the Institute of Molecular Science (ICMol) of the University of Valencia, has achieved spin-electric control in molecular nanomagnets. This fact offers great advantages when preparing quantum devices based on magnetic molecules. The work has been published in the journal Nature Physics.
- How to program DNA robots to poke and prod cell...on October 15, 2021 at 1:45 pm
Scientists have worked out how to best get DNA to communicate with membranes in our body, paving the way for the creation of 'mini biological computers' in droplets that have potential uses in biosensing and mRNA vaccines.