7. - / Origin of Color-Application of UV/Vis Spectroscopy on Cyanine dye 1.. π 3. particle in one dimensional box 4. / 5. Beer s law 1.. / UV/VIS Spectrometer 3. / 1.. / (i) (ii) Beer s law (ε) (iii) λ max L experiment (iv) L estimate (v) (vi) 3. L experiment L estimate 4. [L [ experiment λ max ] 1
7. - / Origin of Color-Application of UV/Vis Spectroscopy on Cyanine dye / particle in one-dimension box particle in one-dimension box / / π - http://instruct.uwo.ca/chemistry/3b-98/colours.htm http://www.chemistry.nmsu.edu/studntres/chem435/lab5/ http://www.uwplatt.edu/chemep/chem/chemscape/labdocs/catofp/measurea/concentr /spec0/fspec0.htm http://www.chem.unl.edu/uic/uv_links.html http://www.shsu.edu/%7echm_tgc/sounds/db.mov
(selective absorption) (scattering) (1) E photon (=hν; ν h Plank constant) E photon = hν = E molecule = E upper state E lower state (rotation) (vibration) (electronic energy) (ground state; ) (excited state) (transitions) (conjugated sytem) (ethylene; C H 4 )) sp (hybrid orbital) 1s sp σ p- π σ π (conjugation) 1,3- butadien 3
π p polyen polyen (dye) polyene β lycopene polyen λ 450 ~ 460 nm (chromophore polyene (a) β (b) lycopene lycopene p π (particle in a one-dimension box) 4
Particle in a one-dimension box m (x) L (0 x L) 0 x L Schrödinger equation () d ψ 0 + ψ = E m dx () ћ=h/πh Plank constant (=6.66 10-34 )ψ m E nπx ψ n = sin n=1,, 3. (3) L L (3)n n h E n = 8mL n=1,,3... (4) n 0 h / 8 ml (zero-point energy (4) E h E = En + 1 En = ( n + 1) (5) 8mL 5 L E L E 3 (b) ( a n (4) (c) L ψ (molecular orbital) (orbital energy) 5
ψ (a) (b) (c) (Cyanine) Dye A 1,1'-Diethyl-,'-cyanine iodide Dye B 1,1'-Diethyl-,'-carbocyanine iodide Dye C 1,1'-Diethyl-,'-dicarbocyanine iodide Dye D 1,1'-Diethyl-4,4'-cyanine iodide Dye E 1,1'-Diethyl-4,4'-carbocyanine iodide Dye F 1,1'-Diethyl-4,4'-dicarbocyanine iodide 6
(N) box (walls Dye C (resonance) σ π Dye B 8 π N + 3 4 Dye B π n=4 (highest filled orbital n=5 (lowest unfilled orbital Dye B π n = 4 n = 5 5 6 E = E h 8mL ( 5 ) 5 E4 = 4 7
hνhλ n LUO n HFO [(n+1) -n ]=n+16 8mcL λ = 7 (n + 1) h 7 m c h n λ L m = 9.1 kg c =.99 m s -1 Plank h = 6.6 J s π 7 λ max / m cplank h n λ max (7) cyanine iodide (L) Dye A λ max 54.5 nm Dye A 6 π ( LUO HFO ) n n hλ 34 9 max (4 3 )(6.66 10 Js)(54.5 10 m) L = = mc 31 8 8 8(9.11 10 kg)(.998 10 m/s) =1.05 10-9 m=1.05nm 8
1.39Ǻ Dye A 6 (0.139 nm) 68.3 10-10 / / 1 cm / (cuvette; 1 c ) 1,1'-Diethyl-,'-cyanine iodide; 1,1'-Diethyl-,'-carbocyanine iodide; 1,1'-Diethyl-4,4'-cyanine iodide; 1,1'-Diethyl-,'-dicarbocyanine iodide; 1,1'-Diethyl-4,4'-carbocyanine iodide; 1,1'-Diethyl-4,4'-dicarbocyanine iodide; (methanol; HPLC ) 1. Dye A ~ Dye F ( 10 4 M ). 10 5 M 3. / 1. Dye A ~ Dye F 1 ml /. / 300 nm 900 nm 3. maximum absorbance 1 1 4. (λ max ) 9
Dye A ~ Dye F / 1. Excel. (λ max ) 3. Beer s law (ε) 4. λ max 7 L experiment (box π ) 5. 1.39 Ǻ0.139 nm L estimate 6.,L experiment,, λ max, Dye A ~ C Dye D ~ F λ λ (M) max (nm) A(nm) DyeA DyeB DyeC DyeD DyeE DyeF 1.0 10-5 5.97 0.741 7410 3.3 10-6 604.01 0.5808 176000 5.0 10-6 706.4 0.6051 1100 1.0 10-5 589.73 0.8184 81840.5 10-6 706.18 0.6631 6540 5.0 10-6 81.75 0.5588 111760 1.. Beer s law Dye A : 3. L 0.741 = ε(1 cm)(1.0 10-5 M ) ε= 7410 cm 1 Μ 1 ( LUO HFO ) n n hλ 34 9 max (4 3 )(6.66 10 Js)(5.97 10 m) = = 8mc 8(9.11 10 kg)(.998 10 m/s) experiment, A 31 8 =1.05 nm 10
4. experiment 1.05 nm 1.8 nm 1.53 nm 1.4 nm 1.67 nm 1.9 nm 5.97 nm 604.01 nm 706.4 nm 589.73 nm 706.18 nm 81.75 nm Dye A ~ C Dye D~F λ max π Dye A Dye B Dye C Dye D Dye E Dye F ( ) 1. R. A. Potts, Journal of Chemical Education, 51, 539, 1974.. B. D, Anderson, Alternaltive Compounds for the Particle in a Box Experiment, Journal of Chemical Education, 74 (8), 985, 1997. 3. G. Nibler, and Shoemaker; Experiments in Physical Chemistry 7 th editon, McGrawHill, 003, p.380-385. 11
7. mmhg 1. Dye A Dye B Dye C Dye D Dye E Dye F (M) ml (M). λ max (nm) Dye A Dye B Dye C Dye D Dye E Dye F (M) ε L (nm) L (nm) 1
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