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| {{One source|date=August 2009}}
| | Greetings. The writer's name is Phebe and she feels comfy when individuals use the full title. North Dakota is exactly where me and my husband live. I am a meter reader. Body building is 1 of the issues I adore most.<br><br>Check out my weblog [http://Www.Animecontent.com/blog/124234 std home test] |
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| A '''photochemical logic gate''' is based on the [[photochemical]] [[intersystem crossing]] and [[molecular electronic transition]] between photochemically active molecules, leading to logic gates that can be produced.<ref Name="Karlin">{{cite book
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| |title= Progress in Inorganic Chemistry
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| |last= Karlin
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| |first= Kenneth D.
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| |authorlink= Kenneth D. Karlin
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| |coauthors=
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| |year= 2009
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| |publisher= Wiley-Interscience
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| |location=
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| |isbn= 0-470-39547-8
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| |page= 458
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| |pages=
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| |url= http://books.google.com/books?id=9XkDaYZoyXAC&pg=PA458&dq=Photochemical+logic+gate&client=firefox-a#v=onepage&q=Photochemical%20logic%20gate&f=false}}</ref>
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| ==The OR gate electron–photon transfer chain==
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| {{unreferenced section|date=August 2006}}
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| _A* A* = excited state of molecule A <br/>
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| _B*<br/>
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| _C*
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| _A _B _C
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| The [[logical conjunction|OR]] gate is based on the activation of molecule A, and thus pass [[electron]] / [[photon]] to molecule C’s excited state orbitals ( C*). The electron from molecule A inter system crosses to C* via the excited state orbitals of B, eventually utilised as a signal in the C* h<math>\upsilon_{c}</math> emission. The ‘[[logical conjunction|OR]]’ gate uses two inputs of light (photons) to molecule A in two separate electron transfer chains, both of which are capable of transferring to C* and thus producing the output of an [[logical conjunction|OR]] gate. Therefore, if either electron transfer chain is activated, molecule C’s excitation produces a valid/ output emission.
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| Input Input<br/>
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| A D<br/>
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| <math>\searrow</math> <math>\swarrow</math><br/>
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| B E<br/>
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| <math>\searrow</math><math>\swarrow</math><br/>
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| C<br/>
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| output <br/>
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| ==The ‘AND’ gate==
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| {{unreferenced section|date=August 2006}}
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| _C** Second excited state of molecule C<br/>
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| _A*<br/>
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| _B*<br/>
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| _C*<br/>
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| <br/>
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| _A _B _C
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| Excitation A<math>\rightarrow</math>A* by h<math>\upsilon_{a}</math> photon, whereby the promoted electron is passed down to the C* molecular orbital. A second photon applied to the system (h<math>\upsilon_{c2}</math>) causes the excitation of the electron in the C* molecular orbital to the C** molecular orbital -analogous pump probe spectroscopy.
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| _* * Second excited state of molecule C
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| <math>\uparrow</math>h<math>\upsilon_{c2}</math><br/>
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| _*
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| <math>\uparrow</math>h<math>\upsilon_{c}</math>
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| _C
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| Above, the energy level diagram illustrating the principle of pump probe spectroscopy –the excitation of an excited state.
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| The [[logical conjunction|AND]] gate is produced by the necessity of both A<math>\rightarrow</math>A* and the C**<math>\rightarrow</math>C excitations occurring at the same time -input h<math>\upsilon</math> and h<math>\upsilon</math>, are simultaneously required.
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| To prevent erroneous emissions of light from a single input to the [[logical conjunction|AND]] gate, it would be necessary to have an electron transfer series with ability accept any [[electron]]s (energy) from C* energy level. The electron transfer series would terminate with a low (non-radiative decay) of the energy
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| The alternatives for producing an [[logical conjunction|AND]] gate, using molecular photphysics, are two.
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| (1) The emission produced by the electron drop from C*<math>\rightarrow</math>C (h<math>\upsilon_{c}</math>) is not a valid output frequency. The emission from the C** (h<math>\upsilon_{c}</math> + h<math>\upsilon_{c2}</math>, h<math>\upsilon_{c3}</math>) molecular orbital is a valid output signal;. to be used in subsequent logic gates -arranged to respond to the C**<math>\rightarrow_{c2}</math>C emission.
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| The second input of [[photon]](s) to trigger the rapid conversion of a molecule used to complete the electron transfer chain. A very complex molecule like a protein can be engineered to possess high strain energies, so that in the absence of the second light frequency molecule B is inactive (B). The second photon input triggers B<math>\rightarrow</math>B' where the forward rate constant is much smaller than the reverse. If such a molecule is used as molecule B, the transfer chain can be switched on and off.
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| ==Creating the NOT gate==
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| {{unreferenced section|date=August 2006}}
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| To stop the [[electron]] transfer chain completing, producing output signals, the input of a [[photon]], h<math>\upsilon_{c2}</math>, is used to produce a ‘pump probe spectroscopy’ effect by promoting an electron in an electron transfer chain. The fall of the pump probe promoted electron produces an output that is quenched down an electron transfer chain.
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| An alternative is similar to the [[logical conjunction|AND]] gate alternative; an input causes a change in molecule structure breaking the electron transfer chain by not allowing the smooth energy transfer of electrons.
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| ==See also==
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| *[[Photohydrogen]]
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| *[[Artificial photosynthesis]]
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| *[[Photocatalysis]]
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| *[[Photodissociation]]
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| *[[Photoelectrolysis]]
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| *[[Photosynthesis]]
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| *[[Photochemical reaction]]
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| *[[Photochemistry]]
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| ==References==
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| {{reflist}}
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| [[Category:Photochemistry]]
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| [[Category:Logic gates]]
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| [[Category:Molecular electronics]]
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Greetings. The writer's name is Phebe and she feels comfy when individuals use the full title. North Dakota is exactly where me and my husband live. I am a meter reader. Body building is 1 of the issues I adore most.
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