Chapter 7 ultraviolet absorption spectrometry *--1--1--1----1--4--1--1---- Section 1 Principles of UV spectrometry Section 2 UV-vis spectrophotometer Section 3 Application of UV spectrometry
Chapter 7 ultraviolet absorption spectrometry Section 1 Principles of UV spectrometry Section 2 UV-vis spectrophotometer Section 3 Application of UV spectrometry
Section 1 Principles of UV spectrometry 1 Molecular absorption spectrometry Electron energy level Ee Vibration energy level Ev Rotation energy level Er E=Ee+Ey+ er MEe >AEv >MEr
E＝Ee + Ev + Er ΔEe >ΔΕv >ΔΕr Electron energy level Ee Vibration energy level Ev Rotation energy level Er 1 Molecular absorption spectrometry Section 1 Principles of UV spectrometry
V"=0 B 3 纯电子 6 2跃迁 4 0-2 6420 纯转动纯振动 跃迁跃迁y=0 A 双原子分子的三种能级跃迁示意图
1eV=16×10-J △E=E,-E1=hv=h=6625×1034J·s =4.14×10eV·s hc4.14×10-5eV.s×2.998×1010cm.s-1 △E △E (1) rotation:ABr:0.005~0.050eV,248-25um (2) vibration: 4 Ev: 0.051 eV, 25- 1. 2 um (3) electron: 4 Ee: 1--20eV 1200-62nm
E eV s cm s E hc = = −1 5 1 0 −1 4.14 10 2.998 10 （1） rotation:ΔΕr：0.005～0.050eV，248 - 25 m （2） vibration:ΔΕv：0.05～１eV， 25 - 1.2 m （3） electron:ΔEe:1～20eV, 1200 – 62 nm hc E = E2 − E1 = h = eV s h J s eV J = = = − − − 15 34 19 4.14 10 6.625 10 1 1.6 10
紫外吸收光谱:分子价电子能级跃迁。 波长范围:100-800mm (1)远紫外光区:100-200nm (2)近紫外光区:200400m (3)可见光区:400-800nm
紫外吸收光谱：分子价电子能级跃迁。 波长范围：100-800 nm. (1) 远紫外光区: 100-200nm (2) 近紫外光区: 200-400nm (3)可见光区: 400-800nm