Zero differential overlap is an approximation in computational molecular orbital theory that is the central technique of semi-empirical methods in quantum chemistry. When computers were first used to calculate bonding in molecules, it was only possible to calculate diatomic molecules. As computers advanced, it became possible to study larger molecules, but the use of this approximation has always allowed the study of even larger molecules. Currently semi-empirical methods can be applied to molecules as large as whole proteins. The approximation involves ignoring certain integrals, usually two-electron repulsion integrals. If the number of orbitals used in the calculation is N, the number of two-electron repulsion integrals scales as N4. After the approximation is applied the number of such
| Attributes | Values |
|---|
| rdf:type
| |
| rdfs:label
| - Sovrapposizione zero-differenziale (it)
- ゼロ微分重なり (ja)
- Zero differential overlap (en)
|
| rdfs:comment
| - ゼロ微分重なり（ゼロびぶんかさなり、英: Zero differential overlap、微分重なりの無視）は、計算分子軌道法における近似であり、量子化学における半経験的手法の中心となる手法である。計算機が分子中の結合を計算するために最初に用いられた時、二原子分子について計算することしかできなかった。計算機が進歩するにつれて、より大きな分子の研究が可能になったが、この近似を用いることでさらに大きな分子の研究が常に可能になっている。現在、半経験的手法は全長のタンパク質ほど大きな分子にも適用できる。この近似には、特定の積分、大抵は2電子反発積分の無視が含まれる。計算に用いられるオービタルの数がNとすると、2電子反発積分の数はN4で拡大縮小する。この近似の適用後、こういった積分の数はN2とかなり小さくなり、計算が単純化される。 (ja)
- Zero differential overlap is an approximation in computational molecular orbital theory that is the central technique of semi-empirical methods in quantum chemistry. When computers were first used to calculate bonding in molecules, it was only possible to calculate diatomic molecules. As computers advanced, it became possible to study larger molecules, but the use of this approximation has always allowed the study of even larger molecules. Currently semi-empirical methods can be applied to molecules as large as whole proteins. The approximation involves ignoring certain integrals, usually two-electron repulsion integrals. If the number of orbitals used in the calculation is N, the number of two-electron repulsion integrals scales as N4. After the approximation is applied the number of such (en)
- La sovrapposizione zero-differenziale è un'approssimazione che ignora alcuni integrali, solitamente quelli legati alla repulsione tra due elettroni, utilizzata nei calcoli semiempirici di chimica quantistica. Se gli orbitali molecolari sono espansi in termini di N funzioni base, , come dove A è l'atomo a cui si riferisce la funzione base e sono i coefficienti. Gli integrali di repulsione tra due elettroni sono definiti da L'approssimazione della sovrapposizione zero-differenziale ignora gli integrali che contengono il prodotto , dove è diverso da . Questo conduce all'uguaglianza dove (it)
|
| dcterms:subject
| |
| Wikipage page ID
| |
| Wikipage revision ID
| |
| Link from a Wikipage to another Wikipage
| |
| Link from a Wikipage to an external page
| |
| sameAs
| |
| dbp:wikiPageUsesTemplate
| |
| has abstract
| - La sovrapposizione zero-differenziale è un'approssimazione che ignora alcuni integrali, solitamente quelli legati alla repulsione tra due elettroni, utilizzata nei calcoli semiempirici di chimica quantistica. Se gli orbitali molecolari sono espansi in termini di N funzioni base, , come dove A è l'atomo a cui si riferisce la funzione base e sono i coefficienti. Gli integrali di repulsione tra due elettroni sono definiti da L'approssimazione della sovrapposizione zero-differenziale ignora gli integrali che contengono il prodotto , dove è diverso da . Questo conduce all'uguaglianza dove In tale modo il numero complessivo di integrali viene ridotto a N(N+1)/2 (approssimativamente N2/2) da [N(N+1)/2][N(N+1)/2 + 1]/2 (approssimativamente N4/8), caratteristici dei metodi ab initio Hartree-Fock e post Hartree-Fock. Metodi quali il e il CNDO/2 utilizzano l'approssimazione della sovrapposizione zero-differenziale in modo completo. Altri metodi, come e successivi derivati, sono basati su un utilizzo intermedio della sovrapposizione differenziale mentre altri ancora trascurano la sovrapposizione differenziale tra due atomi (diatomica). (it)
- Zero differential overlap is an approximation in computational molecular orbital theory that is the central technique of semi-empirical methods in quantum chemistry. When computers were first used to calculate bonding in molecules, it was only possible to calculate diatomic molecules. As computers advanced, it became possible to study larger molecules, but the use of this approximation has always allowed the study of even larger molecules. Currently semi-empirical methods can be applied to molecules as large as whole proteins. The approximation involves ignoring certain integrals, usually two-electron repulsion integrals. If the number of orbitals used in the calculation is N, the number of two-electron repulsion integrals scales as N4. After the approximation is applied the number of such integrals scales as N2, a much smaller number, simplifying the calculation. (en)
- ゼロ微分重なり（ゼロびぶんかさなり、英: Zero differential overlap、微分重なりの無視）は、計算分子軌道法における近似であり、量子化学における半経験的手法の中心となる手法である。計算機が分子中の結合を計算するために最初に用いられた時、二原子分子について計算することしかできなかった。計算機が進歩するにつれて、より大きな分子の研究が可能になったが、この近似を用いることでさらに大きな分子の研究が常に可能になっている。現在、半経験的手法は全長のタンパク質ほど大きな分子にも適用できる。この近似には、特定の積分、大抵は2電子反発積分の無視が含まれる。計算に用いられるオービタルの数がNとすると、2電子反発積分の数はN4で拡大縮小する。この近似の適用後、こういった積分の数はN2とかなり小さくなり、計算が単純化される。 (ja)
|
| gold:hypernym
| |
| prov:wasDerivedFrom
| |
| page length (characters) of wiki page
| |
| foaf:isPrimaryTopicOf
| |
| is Link from a Wikipage to another Wikipage
of | |
| is Wikipage redirect
of | |
| is foaf:primaryTopic
of | |
![[cxml]](/fct/images/cxml_doc.png)
![[csv]](/fct/images/csv_doc.png)
![[text]](/fct/images/ntriples_doc.png)
![[turtle]](/fct/images/n3turtle_doc.png)
![[ld+json]](/fct/images/jsonld_doc.png)
![[rdf+json]](/fct/images/json_doc.png)
![[rdf+xml]](/fct/images/xml_doc.png)
![[atom+xml]](/fct/images/atom_doc.png)
![[html]](/fct/images/html_doc.png)
![[RDF Data]](/fct/images/sw-rdf-blue.png)