<\/p>\n<\/p>\n
Todays title<\/a> of the magazine nature<\/a> reported about an experiment<\/a> where the electron transport in a crystall could be observed within an range in the order of 10 attoseconds (10*10^{-18}s= 10 as). It would be interesting to know wether such high temporal resolution could also be used for investigating electron tranfer in pigment-protein complexes such as in a If I understood correctly the electron transfer in the photosynthetic reaction center of Rhodobacter sphaeroides<\/a> in the above experiment seems to be highly efficient due to the long coherence<\/a> between the exiton states of two chromophores<\/a> corresponding to the bacteriochlorophyll b (BChl-b) molecules and bacteriophaeophytin b molecules (BPh) of a photosynthetic reaction center. This coherence seems to be longer than what can explained by something which is called Foerster theory<\/a>(?). On the other hand molecular dynamics simulations on the reaction center of Rhodopseudomonas viridis<\/a> showed that nuclear motions of adjacent chromophores are also strongly correlated. <\/p>\n
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\nThe experiment is also described in todays press release: “capturing electrons on their trip between atoms”<\/a> of the Max-Planch-Institut für Quantenoptik.<\/a> The researchers used two light pulses, an extreme UV<\/a> pulse of 300 attoseconds (which let loose electrons which are either loosely or more strongly bound to the atoms of a Tungsten crystall) and an infrared laser puls (which interacts with the electrons when they reach the surface of the crystall). The let-loose-loosely-bound electrons were 100 attoseconds faster than the let-loose-more-strongly bound electrons. <\/p>\nphotosynthetic reaction center<\/a> (see image above)<\/strike>(correction 05.10.2012: in a FMO complex<\/a> (the reaction center seems to be a part of this complex))<\/span>, which was done by researchers in Berkeley<\/a> e.g. in a 3 pulse two-color electronic photon echo experiment with 750 and 800 nm pulses in the femtosecond range (science 316 (5830)<\/a>) or wether the high energies of the corresponding laser pulses would alter the corresponding structures, which apparently happenes if one shoots with gamma rays on a pigment<\/a>.<\/p>\n
![UV<\/a> pulse of 300 attoseconds (which let loose electrons which are either loosely or more strongly bound to the atoms of a Tungsten crystall) and an infrared laser puls (which interacts with the electrons when they reach the surface of the crystall). The let-loose-loosely-bound electrons were 100 attoseconds faster than the let-loose-more-strongly bound electrons. <\/p>\nIt would be interesting to know wether such high temporal resolution could also be used for investigating electron tranfer in pigment-protein complexes such as in a photosynthetic reaction center<\/a> (see image above)<\/strike>(correction 05.10.2012: in a FMO complex<\/a> (the reaction center seems to be a part of this complex))<\/span>, which was done by researchers in Berkeley<\/a> e.g. in a 3 pulse two-color electronic photon echo experiment with 750 and 800 nm pulses in the femtosecond range (science 316 (5830)<\/a>) or wether the high energies of the corresponding laser pulses would alter the corresponding structures, which apparently happenes if one shoots with gamma rays on a pigment<\/a>.<\/p>\nIf I understood correctly the electron transfer in the photosynthetic reaction center of Rhodobacter sphaeroides<\/a> in the above experiment seems to be highly efficient due to the long coherence<\/a> between the exiton states of two chromophores<\/a> corresponding to the bacteriochlorophyll b (BChl-b) molecules and bacteriophaeophytin b molecules (BPh) of a photosynthetic reaction center. This coherence seems to be longer than what can explained by something which is called Foerster theory<\/a>(?). On the other hand molecular dynamics simulations on the reaction center of Rhodopseudomonas viridis<\/a> showed that nuclear motions of adjacent chromophores are also strongly correlated. <\/p>\nA fast comment – this may be a bit speculative – but the latter mechanism reminds me very much of the formation of Cooper pairs<\/a> via electron phonon interaction. <\/p>\n","protected":false},"excerpt":{"rendered":"(left) a photosynthetic reaction center (rc) and (right) rc + and light harvesting complexes in a membrane (image source) Todays title of the magazine nature reported about an experiment where the electron transport in a crystall could be observed within an range in the order of 10 attoseconds (10*10^{-18}s= 10 as).<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[23,7],"tags":[],"_links":{"self":[{"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=\/wp\/v2\/posts\/1544"}],"collection":[{"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1544"}],"version-history":[{"count":4,"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=\/wp\/v2\/posts\/1544\/revisions"}],"predecessor-version":[{"id":4926,"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=\/wp\/v2\/posts\/1544\/revisions\/4926"}],"wp:attachment":[{"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1544"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1544"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1544"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}](\"http:\/\/en.wikipedia.org\/wiki\/Image:EM_spectrum.svg\"){kind=link}