I-Attosecond pulses iveza izimfihlo zokubambezeleka kwesikhathi

I-Attosecond pulsesyembula izimfihlo zokubambezeleka kwesikhathi
Ososayensi e-United States, ngosizo lwe-attosecond pulses, badalule ulwazi olusha mayelana neumphumela we-photoelectric:ibeukukhishwa kwe-photoelectricukubambezeleka kufika kuma-attoseconds angu-700, isikhathi eside kakhulu kunalokho obekulindelwe ngaphambilini. Lolu cwaningo lwakamuva luphonsela inselelo amamodeli akhona etiyetha futhi lunikela ekuqondeni okujulile ukusebenzisana phakathi kwama-electron, okuholela ekuthuthukisweni kobuchwepheshe obufana nama-semiconductors namaseli elanga.
Umphumela we-photoelectric ubhekisela kwinto yokuthi lapho ukukhanya kukhanya ku-molecule noma i-athomu endaweni yensimbi, i-photon isebenzisana ne-molecule noma i-athomu futhi ikhiphe ama-electron. Lo mphumela awusona nje esinye sezisekelo ezibalulekile ze-quantum mechanics, kodwa futhi unomthelela omkhulu ku-physics yesimanje, i-chemistry kanye nesayensi yezinto ezibonakalayo. Kodwa-ke, kulo mkhakha, lokho okubizwa ngokuthi isikhathi sokulibaziseka kwe-photoemission kube yisihloko esiphikisanayo, futhi amamodeli ahlukahlukene etiyetha aye achaza ngamadigri ahlukene, kodwa akukho ukuvumelana okuhlanganisiwe okwenziwe.
Njengoba umkhakha wesayensi ye-attosecond uthuthuke kakhulu eminyakeni yamuva, leli thuluzi elivelayo linikeza indlela engakaze ibonwe yokuhlola umhlaba onama-microscopic. Ngokulinganisa ngokunembile izenzakalo ezenzeka esikalini sesikhathi esifushane kakhulu, abacwaningi bayakwazi ukuthola ulwazi olwengeziwe mayelana nokuziphatha okuguquguqukayo kwezinhlayiya. Ocwaningweni lwakamuva, basebenzise uchungechunge lwamaphampu e-X-ray anamandla aphezulu akhiqizwa umthombo wokukhanya ohlangene e-Stanford Linac Center (SLAC), owathatha ingxenye yesigidigidi sesekhondi (attosecond), ukuze wenze ionize ama-electron angumongo futhi. "khahlela" ngaphandle kwe-molecule ejabulile.
Ukuze kuqhutshekwe kuhlaziywe ama-trajectories alawa ma-electron akhululiwe, asebenzise ngamunye ejabulileama-laser pulsesukukala izikhathi zokuphuma kwama-electron ngezindlela ezahlukene. Le ndlela yabavumela ukuba abale ngokunembile umehluko obalulekile phakathi kwezikhathi ezihlukene ezibangelwa ukusebenzisana phakathi kwama-electron, okuqinisekisa ukuthi ukubambezeleka kungafinyelela kuma-attoseconds angu-700. Kuyaphawuleka ukuthi lokhu kutholakala akugcini nje ngokuqinisekisa imibono ethile yangaphambilini, kodwa futhi kuphakamisa imibuzo emisha, okwenza izinkolelo-mbono ezifanele zihlolwe kabusha futhi zibuyekezwe.
Ngaphezu kwalokho, ucwaningo lugqamisa ukubaluleka kokulinganisa nokuhumusha lokhu kubambezeleka kwesikhathi, okubalulekile ekuqondeni imiphumela yokuhlolwa. Ku-protein crystallography, imaging yezokwelapha, nezinye izinhlelo zokusebenza ezibalulekile ezihlanganisa ukusebenzisana kwama-X-ray nodaba, le datha izoba yisisekelo esibalulekile sokuthuthukisa izindlela zobuchwepheshe kanye nokuthuthukisa ikhwalithi yokuthwebula. Ngakho-ke, iqembu lihlela ukuqhubeka nokuhlola amandla e-electronic ezinhlobo ezahlukene zama-molecule ukuze kwembule ulwazi olusha mayelana nokuziphatha kwe-elekthronikhi ezinhlelweni eziyinkimbinkimbi kakhulu kanye nobudlelwano bawo nesakhiwo samangqamuzana, lenza isisekelo sedatha esiqine kakhulu sokuthuthukiswa kobuchwepheshe obuhlobene. esikhathini esizayo.