Attosecond pulses amawulula zinsinsi zakuchedwa kwa nthawi

Attosecond pulseskuwulula zinsinsi za kuchedwa kwa nthawi
Asayansi ku United States, mothandizidwa ndi attosecond pulses, awulula zatsopano zokhudzana ndiphotoelectric zotsatira: ndikutulutsa kwamagetsikuchedwa kumafikira ma attoseconds 700, motalika kwambiri kuposa momwe amayembekezera m'mbuyomu. Kafukufuku waposachedwa uku akutsutsa zitsanzo zomwe zilipo kale ndipo zimathandizira kumvetsetsa mozama za kuyanjana pakati pa ma elekitironi, zomwe zimapangitsa kuti pakhale chitukuko chaukadaulo monga ma semiconductors ndi ma cell a solar.
Mphamvu ya photoelectric imatanthawuza chodabwitsa kuti pamene kuwala kumawalira pa molekyulu kapena atomu pamtunda wachitsulo, photon imagwirizana ndi molekyulu kapena atomu ndikutulutsa ma electron. Izi sizili chimodzi mwa maziko ofunikira a quantum mechanics, komanso zimakhudza kwambiri sayansi yamakono, chemistry ndi zipangizo zamakono. Komabe, m'munda uno, nthawi yomwe imatchedwa kuchedwa kwa photoemission yakhala nkhani yotsutsana, ndipo zitsanzo zosiyanasiyana zamaganizo zakhala zikulongosola ku madigiri osiyanasiyana, koma palibe mgwirizano wogwirizana womwe wapangidwa.
Pamene gawo la sayansi ya attosecond lapita patsogolo kwambiri m'zaka zaposachedwa, chida chomwe chikubwerachi chikupereka njira yomwe sinachitikepo yofufuzira dziko losawoneka ndi maso. Poyesa molondola zochitika zomwe zimachitika pamiyeso yanthawi yochepa kwambiri, ochita kafukufuku amatha kudziwa zambiri za machitidwe osinthika a tinthu tating'onoting'ono. Mu kafukufuku waposachedwa, adagwiritsa ntchito ma pulses amphamvu kwambiri a X-ray opangidwa ndi gwero lolumikizana lowunikira ku Stanford Linac Center (SLAC), lomwe lidatenga gawo limodzi la biliyoni imodzi ya sekondi (attosecond), kuti ionize ma elekitironi apakati ndi "kuchotsa" mu molekyulu yosangalatsa.
Kuti apitirize kusanthula njira za ma elekitironi otulutsidwawa, adagwiritsa ntchito payekhapayekhamphamvu za laserkuyeza nthawi zotulutsa ma elekitironi mbali zosiyanasiyana. Njirayi inawalola kuwerengera molondola kusiyana kwakukulu pakati pa nthawi zosiyanasiyana zomwe zimachitika chifukwa cha kugwirizana pakati pa ma electron, kutsimikizira kuti kuchedwa kungafikire 700 attoseconds. Ndikoyenera kudziwa kuti zomwe zapezekazi sizimangotsimikizira malingaliro ena am'mbuyomu, komanso zimadzutsa mafunso atsopano, kupanga malingaliro ofunikira kuti awonedwenso ndikusinthidwa.
Kuonjezera apo, phunziroli likuwunikira kufunika koyezera ndi kutanthauzira kuchedwa kwa nthawiyi, zomwe ndizofunikira kuti timvetse zotsatira zoyesera. Mu crystallography ya mapuloteni, kujambula kwachipatala, ndi ntchito zina zofunika zokhudzana ndi kugwirizana kwa ma X-ray ndi zinthu, deta iyi idzakhala maziko ofunikira pakuwongolera njira zamakono ndikuwongolera khalidwe la kujambula. Choncho, gulu likukonzekera kupitiriza kufufuza mphamvu zamagetsi zamitundu yosiyanasiyana ya mamolekyu kuti awonetsere zatsopano zokhudzana ndi khalidwe lamagetsi muzinthu zovuta kwambiri komanso ubale wawo ndi mapangidwe a maselo, kuika maziko olimba a deta kuti apange matekinoloje okhudzana nawo. mtsogolomu.