The concept of magic numbers in the field of chemistry refers to a specific property (such as stability) for only certain representatives among a distribution of structures. It was first recognized by inspecting the intensity of mass-spectrometric signals of rare gas cluster ions. Then, the same effect was observed with sodium clusters.
17-538: (Redirected from Magic Numbers ) [REDACTED] Look up magic number in Wiktionary, the free dictionary. Magic number may refer to: Science and technology [ edit ] Magic number (chemistry) , number of atoms or molecules forming an exceptionally stable cluster Magic number (physics) , the number of nucleons that results in completely filled nuclear shells Magic number (programming) , either
34-441: A 2018 series of episodes about Mathematics, presented by Hannah Fry . Other uses [ edit ] Magic number (sports) , a number that indicates how close a team is to winning a season title Magic number (oil) , the price per barrel of oil at which an oil exporting nation runs a deficit See also [ edit ] " The Magical Number Seven, Plus or Minus Two ", a 1956 paper by George Miller Magic constant ,
51-418: A model in which the clusters are treated like " superatoms ". According to this model they exhibit atomic-like electronic states , that are labeled S, P, D, F according to their respective angular momentum on the atomic level. Those clusters that have a " closed superatomic shell " configuration have indeed been identified as the most stable ones. This electronic shell closure and the resulting gain in stability
68-604: A nonzero HOMO/LUMO gap. This existence of discrete electronic states was first indicated by the discrepancy between their optical absorption and the predictions of classical Mie scattering . The discrete optical transitions and occurrence of photoluminescence in these species are areas where they behave like molecular, rather than metallic, substances. This molecular optical behavior sharply distinguishes thiolate-protected clusters from gold nanoparticles, whose optical characteristics are driven by Plasmon resonance . Some of thiolate-protected clusters' properties can be described using
85-711: A specific number of protons or neutrons that forms complete nucleon shells . This chemistry -related article is a stub . You can help Misplaced Pages by expanding it . Thiolate-protected gold cluster Thiolate-protected gold clusters are a type of ligand-protected metal cluster , synthesized from gold ions and thin layer compounds that play a special role in cluster physics because of their unique stability and electronic properties. They are considered to be stable compounds. These clusters can range in size up to hundreds of gold atoms, above which they are classified as passivated gold nanoparticles. The wet chemical synthesis of thiolate-protected gold clusters
102-467: A unique identifier or a literal with unexplained meaning Arts and entertainment [ edit ] Magic Numbers (game show) , British 2010 television game show Magic Number (game) , a pricing game on The Price is Right "Magic Number" (song) , a song by Maaya Sakamoto "The Magic Number", a 1990 song by De La Soul from 3 Feet High and Rising The Magic Numbers , a British rock band Magic Numbers or Hannah Fry's Magic Numbers ,
119-420: Is achieved by the reduction of gold(III) salt solutions, using a mild reducing agent in the presence of thiol compounds. This method starts with gold ions and synthesizes larger particles from them, therefore this type of synthesis can be regarded as a "bottom-up approach" in nanotechnology to the synthesis of nanoparticles. The reduction process depends on the equilibrium between different oxidation states of
136-465: Is also well-known. It was greater than representatives Au 102 (p-MBA) 44 with the para-mercaptobenzoice (para-mercapto-benzoic acid, p-MBA) produced ligand. Worthy of note is that in 2013, a structural prediction of the Au 130 (SCH 3 ) 50 cluster, based on Density Functional Theory (DFT) was confirmed in 2015. This result represents the maturity of this field where calculations are able to guide
153-403: Is different from Wikidata All article disambiguation pages All disambiguation pages Magic number (chemistry) In case a gas condenses into clusters of atoms, the number of atoms in these clusters that are most likely to form varies between a few and hundreds. However, there are peaks at specific cluster sizes, deviating from a pure statistical distribution. Therefore, it
170-768: Is responsible for the discrete distribution of a few stable cluster sizes (magic numbers) observed in their synthesis, rather than a quasi-continuous distribution of sizes. Magic numbers are connected with the number of metal atoms in those thiolate-protected clusters which display an outstanding stability. Such clusters can be synthesized monodispersely and are end products of the etching procedure after an addition of excess thiols does not lead to further metal dissolution. Some important clusters with magic numbers are (SG: Glutathione ): Au 10 (SG) 10 , Au 15 (SG) 13 , Au 18 (SG) 14 , Au 22 (SG) 16 , Au 22 (SG) 17 , Au 25 (SG) 18 , Au 29 (SG) 20 , Au 33 (SG) 22 , and Au 39 (SG) 24 . Au 20 (SCH 2 Ph) 16
187-438: The experimental work. The following table features some sizes. In bionanotechnology , intrinsic properties of the clusters (for example, fluorescence ) can be made available for bionanotechnological applications by linking them with biomolecules through the process of bioconjugation . The protected gold particles' stability and fluorescence makes them efficient emitters of electromagnetic radiation that can be tuned by varying
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#1732794270539204-549: The gold and the oxidized or reduced forms of the reducing agent, or thiols. Gold(I)-thiolate polymers have been identified as important in the initial steps of the reaction. Several synthesis recipes exist that are similar to the Brust synthesis of colloidal gold , however the mechanism is not yet fully understood. The synthesis produces a mixture of dissolved, thiolate-protected gold clusters of different sizes. These particles can then be separated by gel electrophoresis ( PAGE ). If
221-429: The metal and the template can act as a stabilizer and steer the final size of the cluster. Some potential templates are dendrimers , oligonucleotides , proteins , polyelectrolytes and polymers . Top-down synthesis of the clusters can be achieved by the "etching" of larger metallic nanoparticles with redox-active, thiol -containing biomolecules. In this process, gold atoms on the nanoparticles' surface react with
238-538: The sum in a magic square Numerology , the belief that numbers can have magic properties Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title Magic number . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Magic_number&oldid=1238567452 " Category : Disambiguation pages Hidden categories: Short description
255-503: The synthesis is performed in a kinetically controlled manner, particularly stable representatives can be obtained with particles of uniform size ( monodispersely ), avoiding further separation steps. Rather than starting from "naked" gold ions in solution, template reactions can be used for directed synthesis of clusters. The high affinity of the gold ions to electronegative and (partially) charged atoms of functional groups yields potential seeds for cluster formation. The interface between
272-440: The thiol, dissolving as gold-thiolate complexes until the dissolution reaction stops; this leaves behind a residual species of thiolate-protected gold clusters that is particularly stable. This type of synthesis is also possible using other non thiol-based ligands. The electronic structure of the thiolate-protected gold clusters is characterized by strongly pronounced quantum effects. These result in discrete electronic states, and
289-465: Was concluded that clusters of these specific numbers of atoms dominate due to their exceptional stability. The concept was also successfully applied to explain the mono-dispersed occurrence of thiolate-protected gold clusters ; here the outstanding stability of specific cluster sizes is connected with their respective electronic configuration. The term magic numbers is also used in the field of nuclear physics . In this context, magic numbers refer to
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