resonance transition
51Magnetochemistry — is concerned with the magnetic properties of chemical compounds. Magnetic properties arise from the spin and orbital angular momentum of the electrons contained in a compound. Compounds are diamagnetic when they contain no unpaired electrons.… …
52MAGNÉTISME — Le magnétisme est l’un des phénomènes qui a le plus frappé l’imagination de l’homme, au point que ce mot désigne aujourd’hui des réalités très diverses: il s’agit d’abord d’une science fort ancienne et néanmoins toujours d’actualité dont le champ …
53Atome — Un atome (grec ancien ἄτομος [atomos], « qui ne peut être divisé »)[1] est la plus petite partie d un corps simple pouvant se combiner chimiquement avec une autre. La théorie atomiste, qui soutient l idée d une matière composée de… …
54Hypervalent molecule — A hypervalent molecule is a molecule that contains one or more main group elements formally bearing more than eight electrons in their valence shells. Phosphorus pentachloride (PCl5), sulfur hexafluoride (SF6), the phosphate (PO43−) ion, chlorine …
55Mechanical filter — Figure 1. A mechanical filter made by the Kokusai Electric Company intended for selecting the narrow 2 kHz bandwidth signals in SSB radio receivers. It operates at 455 kHz, a common IF for these receivers, and is dimensioned 45×15×15 mm ( …
56Mössbauer spectroscopy — A Mössbauer absorption spectrum of 57Fe Mössbauer spectroscopy is a spectroscopic technique based on the Mössbauer effect. This effect, discovered by Rudolf Mössbauer in 1957, consists in the recoil free, resonant absorption and emission of gamma …
57Mathematics and Physical Sciences — ▪ 2003 Introduction Mathematics Mathematics in 2002 was marked by two discoveries in number theory. The first may have practical implications; the second satisfied a 150 year old curiosity. Computer scientist Manindra Agrawal of the… …
58Physical Sciences — ▪ 2009 Introduction Scientists discovered a new family of superconducting materials and obtained unique images of individual hydrogen atoms and of a multiple exoplanet system. Europe completed the Large Hadron Collider, and China and India took… …
59Atomic clock — Nuclear clock redirects here. For the clock as a measure for risk of catastrophic destruction, see Doomsday Clock. For a clock updated by radio signals (commonly but inaccurately called an atomic clock ), see Radio clock. For the album by Zion I …
60SPECTROSCOPIE - Spectroscopie des rayons X — Les principes fondamentaux qui régissent les transitions électroniques du domaine X et qui permettent leur interprétation sont identiques à ceux de la spectroscopie optique. Toutefois, les transitions X présentent des particularités liées au fait …
