Luminescence: hom, txoj kev, thiab daim ntaub ntawv. Thermally tsa luminescence - dab tsi yog qhov no?

Luminescence yog lub tso tawm ntawm lub teeb los ntawm tej yam ntaub ntawv nyob rau hauv ib lub xeev kuj txias. Nws txawv los ntawm hluav taws xob kub lub cev, piv txwv li hlawv ntoo los yog thee, hlau thiab hlau, rhuab ntawm hluav taws xob tam sim no. Kev nyab xeeb ntawm luminescence yog pom:

• Nyob rau hauv neon thiab fluorescent yaj, TV, radar thiab cov ntxaij lim dej ntawm fluoroscopes;
• Hauv cov organic, xws li luminol lossis luciferin nyob rau hauv cov neeg tua hluav taws;
• Nyob rau hauv ib co pigments siv nyob rau sab nraum zoov advertising;
• Nrog xob laim thiab aurora borealis.

Nyob rau hauv tag nrho cov phenomena, lub teeb tawg tsis yog tshwm sim ntawm cua sov cov khoom saum toj no chav tsev kub, yog li nws yog hu ua txias lub teeb. Lub tswv yim muaj nuj nqis ntawm cov luminescent ntaub ntawv yog lawv muaj peev xwm txia ua lub invisible daim ntawv ntawm lub zog mus rau hauv pom lub teeb.

Cov chaw thiab txheej txheem

Lub phenomenon ntawm luminescence tshwm sim los ntawm kev nqus ntawm lub zog los ntawm cov khoom, piv txwv li, los ntawm ib qhov chaw ultraviolet los yog x-ray hluav taws xob, hluav taws xob kab, tshuaj fab tshuaj, thiab lwm yam. Qhov no ua rau lub atom ntawm qhov teeb meem mus rau hauv ib qho kev txaus siab xeev. Vim nws tsis ruaj khov, cov khoom rov qab los rau nws lub xeev qub, thiab lub zog uas tau muab tso tawm yog tso rau hauv daim ntawv ntawm lub teeb thiab / los yog tshav kub. Tsuas yog cov khoom hluav taws xob sab nrauv xwb thiaj li muaj kev koom tes. Cov hauj lwm zoo ntawm luminescence nyob ntawm seb qhov kev hloov siab ntawm kev cia siab zog rau lub teeb. Tus naj npawb ntawm cov ntaub ntawv nrog kev ua tau zoo txaus siv rau kev siv tsawg kuj tsawg.

Luminescence thiab incandescence

Qhov kev cia siab ntawm luminescence tsis yog vim muaj kev cia siab ntawm atoms. Thaum cov ntaub ntawv kub pib ci zog raws li kev ua kom pom, lawv cov atoms yog nyob rau hauv lub xeev muaj kev lomzem. Txawm hais tias lawv vibrate twb nyob rau hauv chav tsev kub, qhov no yog txaus tias hluav taws xob tshwm sim nyob rau hauv cheeb tsam deb sab hauv ntawm lub spectrum. Nrog kev nce ua kom sov, qhov sib txawv ntawm cov hluav taws xob electromagnetic hloov mus rau thaj chaw pom. Ntawm qhov tod tes, thaum kub heev, uas tau tsim, piv txwv li, hauv kev poob siab hlawv, kev sib tsoo ntawm atoms tuaj yeem muaj zog uas cov electrons cais tawm ntawm lawv thiab recombine, emitting teeb. Qhov no, luminescence thiab incandescence ua indistinguishable.

Cov pa dej paug thiab cov dyes

Pa pigments thiab dyes muaj xim, txij li thaum lawv xav txog tias ib feem ntawm cov spectrum uas yog complementary rau lub absorbed. Ib feem me me ntawm lub zog hloov mus rau hauv tshav kub, tab sis tsis muaj hluav taws xob tshwm sim. Yog tias, txawm li ntawd los, cov xim luminescent absorbs hnub ci hauv ib feem ntawm cov spectrum, nws muaj peev xwm xa tawm cov duab uas txawv ntawm cov thaw. Qhov no tshwm sim los ntawm cov txheej txheem hauv kev zom zis los yog cov xim liab, vim tias cov ultraviolet tuaj yeem hloov mus rau qhov pom, piv txwv li, xiav lub teeb. Xws li txoj kev luminescence yog siv rau sab nraud advertising thiab ntxuav cov hmoov. Nyob rau tom kawg rooj plaub, qhov "clarifier" nyob rau hauv cov ntaub so ntswg tsis tsuas yog muaj kev cuam tshuam dawb, tab sis kuj yuav hloov cov ultraviolet hluav taws xob ua xiav, compensating rau lub yellowness thiab mus pab tau txoj dawb.

Kev tshawb nrhiav thaum ntxov

Txawm li cas los xij, lub teeb ci qaum thiab teeb ci ntsa iab ntawm cov hluav taws thiab cov nceb tau ib txwm paub rau noob neej, thawj cov kev tshawb fawb ntawm luminescence pib nrog cov khoom siv hluav taws xob, thaum nyob rau hauv 1603 Vincenzo Cascariolo, ib qho txheeb thiab shoemaker los ntawm Bologna (Ltalis), rhuab ib qho dej ntawm barium sulphate (barite, Heavy spar) nrog thee. Hmoov tau tom qab txias, thaum hmo ntuj tawm lub teeb xiab, thiab Cascariolo pom tias nws tuaj yeem tau txum tim rov qab los ntawm qhov ua kom hmoov av rau tshav ntuj. Cov khoom no yog hu ua "lapis solaris", los yog lub hnub xya pob zeb, vim hais tias cov neeg xav tau kev vam tias nws yuav tig hlau ua rau kub, lub cim uas yog lub hnub. Lub afterglow aroused lub paj ntawm ntau zaum ntawm lub sij hawm uas muab cov khoom thiab lwm lub npe, nrog rau "phosphorus", uas txhais tau hais tias "carrier ntawm lub teeb".

Niaj hnub no lub npe "phosphorus" tsuas yog siv rau cov tshuaj chemical, thaum cov khoom siv microcrystalline luminescent hu ua phosphor. "Phosphorus" Cascario, thaj, yog barium sulphide. Cov khoom ua ntej muag muaj phosphor (1870) yog "Balmain cov xim" - ib qho tshuaj tov kua ntsev. Nyob rau hauv 1866, thawj ruaj phosphor los ntawm zinc sulphide tau piav - ib qho tseem ceeb tshaj plaws nyob rau hauv cov niaj hnub siv tshuab.

Ib qho ntawm cov kev tshawb fawb thawj zaug ntawm luminescence, tshwm sim los ntawm cov ntoo lossis nqaij thiab hluav taws kub, tshwm sim hauv 1672 los ntawm tus kws tshawb fawb txog Askiv Robert Boyle, tab sis nws tsis paub txog lub keeb kwm ntawm lub teeb ci no, txawm li cas los xij tsim tej yam hauv cov hauv paus hauv nruab nrab ntawm cov khoom siv bioluminescent:

• Lub ci yog txias;
• Nws tuaj yeem ua rau tus neeg raug tshuaj lom neeg xws li dej cawv, hydrochloric acid thiab ammonia;
• Hluav taws xob yuav tsum nkag mus rau saum cua.

Xyoo 1885-1887 nws tau pom tias cov khoom muab rho tawm los ntawm West-Indian fireflies (hluav taws kub nplej-taum) thiab ntawm cov suab thaj ntawm folad, thaum tov, tsim teeb.

Thawj cov ntaub ntawv chemiluminescent cov ntaub ntawv tsis yog-biological hluavtaws, xws li luminol, sab hauv 1928.

Chemi- thiab bioluminescence

Feem ntau cov zog tso tawm rau hauv kev tshuaj lom neeg, tshwj xeeb tshaj yog oxidation tshua, muaj daim ntawv ntawm tshav kub. Hauv qee qhov kev tshuam, tab sis, ib feem ntawm nws yog siv los ua kom muaj siab electrons mus rau ntau dua, thiab cov fluorescent molecules ua ntej pib chemiluminescence (CL). Cov kev tshawb fawb qhia tau tias CL yog qhov tshwm sim hauv lub ntiaj teb, tab sis qhov kev siv ntawm luminescence yog me me uas nws yuav tsum tau siv cov kev ceeb toom tsis zoo. Muaj, txawm li cas los xij, qee lub tebchaw uas ua rau pom CL ci ntsa iab. Qhov feem ntau nrov ntawm cov no yog luminol, uas, thaum oxidized nrog hydrogen peroxide, muaj peev xwm tsim muaj zog xiav los yog xiav-ntsuab lub teeb. Lwm yam muaj zog CL-tshuaj yog lucigenin thiab lofin. Txawm hais tias lawv ci ntsa iab ntawm lawv CL, tsis yog txhua tus neeg siv tau hloov cov khoom siv hluav taws xob mus rau hauv lub teeb, vim tsawg tshaj li 1% ntawm cov lwg me ntsis. Nyob rau hauv xyoo 1960 nws tau pom tias oxalic acid esters oxidized nyob rau hauv anhydrous solvents nyob rau hauv muaj cov fluorescent aromatic sib txuas ua ke emit ci teeb nrog ib tug efficiency ntawm mus txog 23%.

Bioluminescence yog ib hom tshwj xeeb ntawm CL catalyzed by enzymes. Qhov luminescence yield ntawm xws tshua muaj peev xwm ncav cuag 100%, uas txhais tau hais tias txhua lub molecule ntawm reacting luciferin kis mus rau hauv ib lub xeev radiating. Tag nrho cov kab mob bioluminescent paub niaj hnub no yog catalyzed los ntawm oxidation tshua noj chaw nyob rau hauv muaj huab cua.

Thaj plaws tsa tau luminescence

Thermoluminescence txhais tau hais tias tsis thermal hluav taws xob, tab sis kev txhawb zog ntawm lub teeb emission ntawm cov ntaub ntawv uas nws electrons yog siab los ntawm tshav kub. Thaj plaws tsa tau luminescence tau pom hauv qee cov zaub mov, thiab tshwj xeeb tshaj yog nyob rau hauv crystallophosphors tom qab lawv tau raug siab los ntawm lub teeb.

Photoluminescence

Photoluminescence, uas tshwm sim los ntawm kev cuam tshuam los ntawm kev siv hluav taws xob hauv lub cev, muaj peev xwm raug kwv yees nyob ntawm qhov pom ntawm lub teeb pom los ntawm ultraviolet rau X-txoj kab xoo thiab gamma hluav taws xob. Nyob rau hauv luminescence los ntawm photons, lub wavelength ntawm lub teeb emitted yog, raws li txoj cai, vaj huam sib luag los yog siab tshaj lub wavelength ntawm exciting (piv txwv li sib npaug los yog tsawg zog). Qhov sib txawv hauv wavelength yog vim muaj kev hloov ntawm lub zog mus ua vibrations ntawm atoms lossis ions. Qee lub sij hawm, nrog kev raug mob rau lub teeb meem ntawm lub teeb meem, lub teeb uas muaj teeb meem tuaj yeem muaj peev xwm tshee.

Qhov tseeb tias PL tau raug siab heev los ntawm ultraviolet hluav taws tau nrhiav tau los ntawm German physicist Johann Ritter nyob rau hauv 1801. Nws pom hais tias lub phosphors ci ntsa iab hauv cheeb tsam pom qab ntawm lub violet ib feem ntawm lub spectrum, thiab yog li nrhiav qhov UV tawg. Kev hloov ntawm UV mus rau hauv pom lub teeb yog ntawm qhov tseem ceeb uas tseem ceeb.

Gamma thiab x-rays siab phosphors, thiab lwm yam crystalline ntaub ntawv mus rau lub luminescence lub xeev los ntawm ionization txheej txheem ua raws li los ntawm recombination ntawm electrons thiab ions, uas luminescence tshwm sim. Nws pom siv cov tshuaj fluoroscopes siv hauv X-ray diagnostics thiab hauv scintillation counters. Lub tom kawg ntes thiab ntsuas gamma hluav taws xob qhia ntawm lub disc coated nrog ib phosphor uas yog nyob rau hauv qhov muag kov nrog qhov chaw ntawm lub photomultiplier.

Triboluminescence

Thaum cov iav ci ntawm qee yam, xws li qab qab zib, yog crushed, sparks pom. Tib yam tau pom hauv ntau cov organic thiab cov khoom tsis haum. Tag nrho cov hom luminescence no yog tsim los ntawm tus nqi hluav taws xob zoo thiab tsis zoo. Lub tom kawg yog tsim los ntawm kev sib cais txhua yam ntawm cov chaw thiab nyob rau hauv tus txheej txheem ntawm crystallization. Lub teeb tawg ces tshwm sim los ntawm kev tso tawm - txawm ncaj qha, nruab nrab ntawm cov khoom tawg, los yog kev cia siab ntawm lub luminescence ntawm qhov chaw nyob ze ntawm lub qhov sib cais.

Electroluminescence

Zoo nkaus li thermoluminescence, lub sij hawm electroluminescence (EL) muaj ntau hom kev luminescence, qhov sib txawv ntawm qhov uas lub teeb raug tawm ntawm hluav taws xob tawm hauv cov roj, kua thiab cov khib nyiab. Nyob rau hauv 1752, Benjamin Franklin tsim cov luminescence ntawm hluav taws xob, tshwm sim los ntawm kev tso tawm hluav taws xob los ntawm cov chaw. Thaum xyoo 1860, muaj teeb pom kev zoo rau thawj zaug nyob hauv Royal Society of London. Nws tsim lub teeb ci dawb thaum lub siab raug tawm ntawm carbon dioxide thaum tsis tshua muaj siab. Niaj hnub nimno Fluorescent lub teeb nyob rau ntawm ib qho kev sib txuas ntawm electroluminescence thiab photoluminescence: mercury atoms nyob rau hauv ib lub teeb zoo siab los ntawm kev tso tawm hluav taws xob, ultraviolet hluav taws xob tawm los ntawm lawv yog hloov mus rau hauv pom lub teeb ntawm phosphor.

EL pom hauv electrodes thaum lub sij hawm hluav taws xob yog vim ion recombination (li, nws yog hom tshuaj chemiluminescence). Nyob rau hauv kev ntawm ib tug hluav taws xob nyob rau hauv lub teeb txheej ntawm luminescent zinc sulphide, lub teeb yog tawm, uas yog tseem hu ua electroluminescence.

Ntau cov khoom siv emit glow nyob rau hauv tus ntawm accelerated electrons - pob zeb diamond, ruby, crystalline phosphorus thiab ib co platinum ntsev salts. Thawj thawj daim ntawv thov cathodoluminescence yog oscilloscope (1897). Zoo li cov ntxaij uas siv koog tsev kawm ntawv zoo nkauj tuaj yeem siv hauv TVs, radar, oscilloscopes thiab electron microscopes.

Radioluminescence

Radioactive ntsiab tau emit alpha particles (helium nuclei), electrons thiab gamma rays (high-energy electromagnetic radiation). Radiation luminescence yog ib lub luminescence zoo siab los ntawm cov tshuaj yeeb dej caw. Thaum twg alpha cov ntsiab lus muaj bombarded nrog crystalline phosphorus, qhov muag me me yog pom hauv lub tshuab. Qhov no txoj ntsiab cai siv lus Askiv physicist Ernest Rutherford, los ua pov thawj hais tias cov atom muaj ib tug central tub ntxhais. Cov duab xim rau nws tus kheej, siv rau cov cim cov cim thiab lwm yam twj paj nruag, ua haujlwm ntawm lub hauv paus radar. Lawv muaj cov phosphor thiab cov yeeb tshuaj, xws li tritium lossis radium. Txuj kev zoo nrhav luminescence yog lub teeb nrug qaum teb: kev xyum ua num ntawm lub tshooj pov cov luj masses ntawm electrons hab ions rua qhov chaw. Thaum lawv mus rau lub ntiaj teb, nws qhov chaw geomagnetic coj lawv mus rau tus ncej. Roj-paug cov txheej txheem nyob rau hauv cov txheej sab saud ntawm lub chaw ua lub npe nrov ncov qaum.

Luminescence: tus physics ntawm tus txheej txheem

Lub zeem muag ntawm pom lub teeb (piv txwv li, nrog cov piam ntaws ntawm 690 nm thiab 400 nm) yuav tsum muaj lub zog excitation, qhov tsawg kawg nkaus uas yog txiav txim los ntawm Einstein txoj cai. Lub zog (E) yog sib npaug ntawm Planck tas li (h) multiplied los ntawm lub teeb zaus (ν) los yog nws qhov ceev ntawm cov khoom nqus (s) muab faib los ntawm lub wavelength (λ): E = hν = hc / λ.

Yog li, lub zog yuav tsum tau txhaj rau excitation ranges los ntawm 40 kilocalories (rau liab) rau 60 kilocalories (rau daj) thiab 80 kilocalories (rau violet) rau ib qhov khoom ntawm cov khoom. Lwm txoj kev uas tau hnov txog lub zog - nyob rau hauv electron volts (1 eV = 1,6 × 10 ^-12 erg) - los ntawm 1.8 mus 3.1 eV.

Lub zog excitation raug xa mus rau electrons lub luag hauj lwm rau luminescence, uas dhia los ntawm lawv cov theem pib lub zog rau ib qho siab zog. Cov xeev no yog txiav txim los ntawm cov cai ntawm quantum mechanics. Lub tswv yim sib txawv ntawm seb nws tshwm sim nyob rau hauv tib lub nruab nrab thiab cov khoom xyaw, hauv kev sib xyaw ntawm molecules los yog hauv ib qho siv lead ua. Lawv yog pib los ntawm qhov kev txiav txim ntawm cov qauv ceev, xws li electrons, zoo ions los yog photons.

Feem ntau qhov excitation zog yog ntau tshaj li qhov tsim nyog los nce lub electron mus rau theem ntawm hluav taws xob. Piv txwv, glow ntawm phosphor crystals nyob rau hauv TV tshooj yog tsim los ntawm cathode electrons nrog nruab nrab energies ntawm 25,000 electron-volts. Cuaj kaum, xim ntawm fluorescent lub teeb yog yuav luag independent ntawm lub zog ntawm ib qhov me me. Nws yog cuam tshuam los ntawm theem ntawm kev txaus siab lub xeev ntawm lub zog ntawm crystalline cov chaw.

Fluorescent yaj

Qhov hais, vim yog qhov luminescence tshwm sim, yog cov txheej electrons ntawm atoms lossis molecules. Hauv cov roj fluorescent, piv txwv li, mercury atom yog zoo siab los ntawm kev siv zog 6.7 eV los yog tshaj, raising ib qho ntawm ob sab nrauv electrons mus rau ib qib siab dua. Tom qab nws xa rov qab mus rau hauv av hauv lub xeev, qhov txawv ntawm lub zog yog radiated nyob rau hauv daim ntawv ntawm ultraviolet lub teeb nrog ib tug wavelength ntawm 185 nm. Cov kev hloov ntawm lub hauv paus thiab ib theem ua ultraviolet tawg ntawm 254 nm, uas nyob rau hauv lem, yuav ua kom muaj siab lwm phosphor generating pom lub teeb.

Qhov no tawg yog tshwj xeeb yog mob siab heev thaum uas tsis muaj siab mercury vapor (10 ^-5 cua) siv nyob rau hauv cov roj paug teeb ntawm tsis tshua muaj siab. Yog li txog 60% ntawm electron zog yog hloov dua siab tshiab rau hauv ib tug monochromatic UV teeb.

Thaum muaj kev kub ntxhov, qhov ntau zaus nce. Lub spectra tsis muaj ib txoj kab spectral nkaus xwb ntawm 254 nm, thiab lub zog hluav taws xob muab faib rau cov kab ntawm cov qauv sib txawv sib luag: 303, 313, 334, 366, 405, 436, 546 thiab 578 nm. Cov khoom siv hluav taws xob mercury heev yog siv rau kev taws teeb, vim 405-546 nm sib npaug rau lub teeb pom kev-qhov kaj, thiab thaum ib feem ntawm cov hluav taws xob hloov mus rau lub teeb liab nrog kev pab los ntawm phosphor, qhov tshwm sim dawb.

Thaum cov roj lwg me me zoo siab, lawv luminescence spectra qhia sab nrauv; Tsis tsuas yog electrons nce siab dua zog, tab sis tib lub sij hawm vibrational thiab rotational motions ntawm atoms feem ntau yog zoo siab. Qhov no yog vim hais tias vibrational thiab muab lub zog ntawm lub lwg me me yog 10 ^-2 thiab 10 ^-4 ntawm txoj kev hloov energies, uas ntxiv li txhais tau ib plurality ntawm txawv me ntsis wavelength Cheebtsam ntawm ib band. Nyob rau hauv cov kabmob loj, muaj ntau ntau lub bands overlapping, ib qho rau txhua hom kev hloov. Cov duab hluav taws xob tawg rog hauv kev daws teeb meem yog feem ntau ntawm cov qauv, uas yog tshwm sim los ntawm kev sib cuam tshuam ntawm ntau tus neeg muaj siab txaus siab nrog cov kuab tshuaj molecules. Hauv cov molecules, xws li cov atoms, lwm electrons molecular orbitals koom nrog luminescence.

Fluorescence thiab phosphorescence

Cov ntsiab lus uas muaj peev xwm yuav txawv tsis tau tsuas yog raws li nyob rau hauv lub caij ntawm luminescence, tab sis kuj los ntawm nws cov qauv ntawm cov ntau lawm. Thaum ib tug electron yog zoo siab heev rau ib tug singlet lub xeev uas muaj tenure therein 10 ^-8 s, los ntawm uas nws tau yooj yim rov qab mus rau hauv av, cov tshuaj yeeb dej caw emits nws lub zog li fluorescence. Thaum lub sij hawm kev hloov, cov kiv tsis hloov. Basic thiab pog xeev muaj ib tug zoo li multiplicity.

Electron, txawm li cas los, yuav raug tsa mus rau ib tug ntau dua lub zog theem (hu ua "ib tug pog triplet lub xeev") nrog nws rov qab kev kho mob. Nyob rau hauv quantum mechanics, lub zaus ntawm lub triplet lub xeev mus rau lub singlet txwv tsis pub, thiab yog li ntawd, lub sij hawm ntawm lawv lub neej ntau npaum li cas. Yog li ntawd, lub luminescence nyob rau hauv cov ntaub ntawv no yog ntau npaum li cas sij hawm ntev: muaj phosphorescence.