O n t h e T r a c k o f M o d e r n P h y s i c s
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O n t h e T r a c k o f M o d e r n P h y s i c s All difficult words come from Greek. All, but “spectrum”. First used by Cicerone, in Italian means spettro (=ghost), simulacro (= figure or sculpture). Spectroscopy deals with images: a colourful rainbow, a sunset or just the cloudy sky. In other words: spectrum is a ghost and Spectroscopy - a science on ghosts. 40 60 80 100 10 10 2 10 3 10 4 10 5 10 6 10 7 10 8 CH 3 CO-OC 2 H 5 CH 3 CO-OCH 3 CH 3 COOH CH 3 -CO-CH 3 CH 3 OH C 2 H 5 OH CH 3 CHO cps m/e Three upper sky photos are by Carmen Busko, Sao Paolo, Brazil, thanks! http://www.trekearth.com/gallery/South_America/Brazil/ photo89543.htm Remaining photos are by GK. Spectrum is an image, something produced by the object, like the reflected or emitted light. Then You need an analyser, to show single components. This can be a prism, a diffraction grate, but also a snow crystal or a CD-cover. Separated colours, like in a CD form a spectrum. CD-cover “produces” colors, but usually reflecting polarized light, i.e. from blue sky. Unless, the poly- mer is strongly oriented, like here. Colors in CD-cover are complemen- tary, obtained by subtraction of red, blue or green from white. Reflection in azzure on borders of the gold-doped, red ash-tray come from Mie scattering, like in the sky. In the left image no dark blue is present, in the right image no yellow but a lot of red. One is of so-called energetic lamp, one of the morning sky. Can You guess which is which? Reflection from snow does not produce colors, but reflection inside ice crystals does. Separating colors can be done by refraction, like here, diffraction, like to the right, or scattering. Look carefully or snap shots: spectra are everywhere. This is Red See. So, separating features of an object is to make a spectrum. This can be the mass of positive ions in strawberries smell, the energy of photons from an annihilating antimatter, faint hints in the energy dependence for muon production or infrared absorption by silicon. All these, we call spectra. And all are so beautiful for scientists, as a purple morning sky. Hoping, also for You! 0 10 20 30 40 50 1 2 3 4 5 6 7 Mo Ag Cu R a tio to A l P L ( 10 -3 m 0 c ) 1 10 10 N itrog en (N 2 ) D aw erych G ianturco Elza de C arvalho H o ffm an (1982) S ueoka (1984) S ueoka (1993) C h arlton (19 83) P resent T otalcross section (10 -20 m 2 ) P ositron e nerg y (eV ) 300 350 400 450 500 550 600 0 1000 2000 3000 4000 579,0 407,8 576,9 546,1 435,8 404,7 365,5 334,2 313,2 in ten sity (a .u.) w a ve le n g th (n m ) 280 320 360 400 440 480 0 500 1000 1500 2000 w a ve le n g th (n m ) in te n s ity (a .u .) N 2 2 9 5.2 (4,2) N 2 3 1 5 .9 (1 ,0) N 2 4 0 5 .9 (0,3) N 2 3 9 9.8 (1 ,4) N 2 3 7 5.5 (1,3) N 2 3 8 0.5 (0,2) N 2 3 5 7 .7 (0,1) N 2 3 3 7.1 (0,0) Look! how blue can be different! And then, also red is different! Carmem A. Busko Carmem A. Busko Carmem A. Busko 1.0 1 .5 2.0 2.5 3.0 3.5 4.0 4.5 10 15 20 25 30 35 K ennerly convolution 130 m eV tuning I tuning II C ro ss se ctio n (1 0 -2 0 m 2 ) E le ctro n en e rg y (e V ) 1/1
description
Reflection from snow does not produce colors, but reflection inside ice crystals does. CD-cover “produces” colors, but usually reflecting polarized light, i.e. from blue sky. Unless, the poly- mer is strongly oriented, like here. Reflection in azzure on borders of - PowerPoint PPT Presentation
Transcript of O n t h e T r a c k o f M o d e r n P h y s i c s
O n t h e T r a c k o f M o d e r n P h y s i c s
All difficult words come from Greek. All, but “spectrum”. First used by Cicerone, in Italian means spettro (=ghost), simulacro (= figure or sculpture).Spectroscopy deals with images: a colourful rainbow, a sunset or just the cloudy sky.
In other words: spectrum is a ghost and Spectroscopy - a science on ghosts.
40 60 80 100
10
102
103
104
105
106
107
108
CH
3CO
-OC 2
H5
CH
3CO
-OC
H 3
CH
3CO
OH
CH
3-C
O-C
H 3
CH
3OH
C2H
5OH
CH
3CH
O
cps
m/e
Three upper sky photos are by Carmen Busko, Sao Paolo, Brazil, thanks!http://www.trekearth.com/gallery/South_America/Brazil/photo89543.htmRemaining photos are by GK.
Spectrum is an image, something produced bythe object, like the reflected or emitted light.
Then You need an analyser, to show single components. This can be a prism, a diffraction grate, but also a snow crystal or a CD-cover.
Separated colours, like in a CD form a spectrum.CD-cover “produces” colors, but usually reflecting polarized light, i.e. from blue sky. Unless, the poly-mer is strongly oriented, like here.
Colors in CD-cover are complemen-tary, obtained by subtraction of red, blue or green from white.
Reflection in azzure on borders of the gold-doped, red ash-tray come from Mie scattering, like in the sky.
In the left image no dark blue is present, in the right image no yellow buta lot of red. One is of so-called energetic lamp, one of the morning sky.Can You guess which is which?
Reflection from snow does notproduce colors, but reflectioninside ice crystals does.
Separating colors can be done by refraction, like here, diffraction, like to the right, or scattering.
Look carefully or snap shots:spectra are everywhere. This is Red See.
So, separating features of an object is to make a spectrum. This can be the mass of positive ions in strawberries smell, the energy of photons from an annihilating antimatter, faint hints in the energy dependence for muon production or infrared absorption by silicon.
All these, we call spectra. And all are so beautiful for scientists, as a purple morning sky. Hoping, also for You!
0 10 20 30 40 50
1
2
3
4
5
6
7
Mo Ag Cu
Ratio
to A
l
PL ( 10
-3 m
0c )
1 10
10
Nitrogen (N2)
Dawerych Gianturco Elza de Carvalho
Hoffman (1982)Sueoka (1984)
Sueoka (1993) Charlton (1983) Present
Tot
al c
ross
sec
tion
(10
-20 m
2 )
Positron energy (eV)300 350 400 450 500 550 600
0
1000
2000
3000
4000
579,
0
407,
8
576,
9
546,
1
435,
8
404,
7
365,
5
334,
2
313,
2
inte
nsity
(a.
u.)
wavelength (nm)
280 320 360 400 440 480
0
500
1000
1500
2000
wavelength (nm)
inte
nsity
(a
.u.)
N2 295.2
(4,2
)
N2 315.9
(1,0
)
N2 405.9
(0,3
)
N2 399.8
(1,4
)
N2 375.5
(1,3
)
N2 380.5
(0,2
)
N2 357.7
(0,1
)
N2 337.1
(0,0
)
Look! how blue can be different!
And then, also red is different!
Carmem A. BuskoCarmem A. Busko Carmem A. Busko
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
10
15
20
25
30
35
Kennerly convolution 130 meV tuning I tuning II
Cro
ss s
ect
ion
(1
0-20 m
2 )
Electron energy (eV)
1/1
