Valence electrons, nyob hauv lub plhaub sab nraud ntawm ib qho atom, ua lub luag haujlwm tseem ceeb hauv kev tsav cov tshuaj lom neeg thiab tsim cov ntawv sib khi nrog lwm cov atoms.
Tab sis ua kom pom cov lus no thaum lawv ua txoj haujlwm no yog lo qhia. Tsis tsuas yog qhov tseem ceeb ntawm cov tshuab hluav taws xob tsis txaus ntseeg, lawv tseem ua cov kev cai tshuaj tsis pub dhau femtoseconds -}} quadrillions ntawm ib ob.
Tam sim no, kev sim ntawm Lub Chaw Haujlwm Saib Xyuas Lub Zog Cov Seb National National Acceler Sim X {{} {} {} {} {} {} {} {} {} {} {
Siv cov ci ntsa iab tshaj x - ray pulses los ntawm SLAC's Ultrafast LineCov teeb pom kev zoo los ntawm hydrogen dissociation los ntawm ammonia molecule.
Cov txiaj ntsig tau, luam tawm hauv phau ntawv JournalCov tsiaj ntawv soj ntsuam lub cev, tuaj yeem pab cov kws tshawb fawb ob leeg nkag siab cov txheej txheem Chemistry thiab tswj tau zoo dua qub ntawm cov khoom siv tshuaj lom neeg. Qhov kev paub ntawd, nyeg, yuav yog harnessed los tsim tom ntej no-} tiam cov ntaub ntawv thiab thev naus laus zis.
Taug qab qhov tseem ceeb hauv hluav taws xob thaum lub sijhawm
Cov kws tshawb fawb tau sim xyoo los taug qab cov lus tsa suab ntawm ib lub tshuab hluav taws xob thoob plaws hauv kev tshuaj lom neeg. Txawm li cas los xij, kev taug txoj kev taug kev no tau tsim nyog rau ntau qib vim tias nws tau nyuaj rau cais tawm ntawm ib qho atom, thiab nws kuj tau ua tsis tau yog li ntawm lub sijhawmescale tsis tshua muaj tshwm sim.
Ntawm SLAC, cov pab pawg tshawb fawb tau txiav txim siab los sim txoj hauv kev tshiab uas muaj kev cuam tshuam rau ob qho kev xav thiab sim. Siv lub zog ntawm LCLS, ib x - Ray Laser thiab tsis muaj kev sib tham txaus los taug qab cov txheej txheem hauv nruab nrab thiab ua ke nrog cov txheej txheem zoo tshaj plaws thiab kev tshawb nrhiav.
Pab pawg tau coj los ntawm Ian Gabalski, yog Ph.D. Tub ntxhais kawm ntawm Stanford University, Profess Filip Bucksbaum ntawm cov kev xaiv thiab cov ntaub ntawv nyeem uas yuav tsum tau ua rau muaj kev sib tw thiab cov ntaub ntawv tseem ceeb muab los tsim tau tseeb Txais Kev Tsim Khoom Siv Hluav Taws Xob Hluav Taws Xob Hluav Taws Xob Hluav Taws Xob.
Txhawm rau taug qab cov kev cuam tshuam ntawm hluav taws xob cov lus tsa suab, pab pawg tsim ib qho siab ntawm high - ntom ammonia thiab zoo siab nws nrog ultraviolet laser. Raws li lub laser dhau los ntawm cov roj, x {- rays los ntawm LCLs ntaus cov electrons thiab tawg rov qab tawm. "Thiab tag nrho cov khoom tshwm sim hauv chav kawm ntawm 500 femtoseconds," gabalski hais.
Hauv feem ntau cov molecules, cov tseem ceeb hauv hluav taws xob, uas tau nruj nreem khi rau atoms, outnumber lub sab nraud lub chaw siv hluav taws xob. Tab sis nyob rau hauv me me thiab lub teeb molecules zoo li ammonia, uas muaj cov nitrogen atom thiab peb hydrogen atoms, lub peev hluav taws xob hauv hluav taws xob deb tshaj plaws electrons. Qhov ntawd txhais tau tias tus x {{2} i} i} Kev Ristron Scatter ntawm cov hluav taws xob hluav taws xob muaj zog txaus los taug qab cov haujlwm ntawm cov atoms.
Cov kws tshawb fawb twb paub tias los ntawm tus qauv ntawm cov nitrogen thiab hydrogen atoms ua ib qho uas txhua tus atoms pw hauv ib lub dav hlau. Nws thiaj li, ib qho ntawm cov hydrogens tawg tawm ntawm cov phiaj xwm geometry thiab tawg cov molecule. Nrog lawv cov x {{{2} Cov kws tshawb nrhiav duab, cov kws tshawb nrhiav tau tuaj yeem ua kom cov khoom siv hluav taws xob uas tau tsav lub nuclear no.
Sau cov lus suav tau yuam sij rau kev txhais cov ntaub ntawv. "Feem ntau peb yuav tsum infer li cas rau lub sij hawm hloov hluav taws xob tsis tshua pom lawv ncaj qha, tab sis ntawm no kev nthuav dav los ntawm kev ntsuas ntsuas ncaj qha," teev tau hais tias. "Nws yog kev sib koom tes sib raug zoo ntawm kev xav thiab sim."
Tom qab cov tshuaj tiv thaiv sib txawv
Taug qab cov lus tsa suab ntawm kev nrhiav hluav taws xob hluav taws xob kuj muab lub qhov rai rau hauv txoj kev sib txawv uas cov kev coj noj tshuaj uas tuaj yeem siv sijhawm, tsav los ntawm lub suab hluav taws xob.
"Yog tias koj sim ua synthesize ib tug molecule rau cov kws tshuaj ntsuam tshiab lossis cov khoom siv tau ib txwm mus rau hauv ob qho tib si xav tau," Gabalski hais. "Thaum nws tsis mus rau txoj kev uas koj xav tau, nws tsim los ntawm cov kev ua haujlwm no, tom qab ntawd koj tuaj yeem paub yuav ua li cas thiaj li hloov pauv qhov koj xav tau."
Pab neeg vam tias yuav kho tau lawv cov tswv yim zoo dua, tshwj xeeb nrog cov duab hluav taws xob zoo dua li cov kev nce qib li LCL
"Peb tuaj yeem pom cov peev txheej hluav taws xob hauv hiav txwv ntawm cov keeb kwm hluav taws xob ntxiv, uas qhib ntau txoj hauv kev tshiab," Sau hais. "Nws yog cov pov thawj ntawm cov ntsiab lus uas tau thawb peb sim kom pom cov khoom uas peb tsis tau pom ua ntej."
