課程綱要：
1.Introductions
Properties of electromagnetic radiations
Interactions of electromagnetic radiations with matters
Principle in obtaining chemical information from optical spectroscopy
2. Components of Optical Instruments
3. UV/Vis Spectroscopy
Basic Principles in detection, instrumentations, Applications
4. Luminescence Spectroscopy
Basic Principles in detection, instrumentations, Applications
5. Infrared Spectroscopy
Basic Principles in detection, instrumentations, Applications
6. Near Infrared Spectroscopy
Basic Principles in detection, instrumentations, Applications
7. Raman Spectroscopy
Basic Principles in detection, instrumentations, Applications
8. Spectroscopy for Surface Analysis
Basic Principles in detection, instrumentations, Applications
9. Nuclear Magnetic Resonance Spectroscopy
Basic Principles in detection, instrumentations, Applications
10. Atomic Spectroscopy
Basic Principles in detection, instrumentations, Applications
參考書：
書名
Principles of instrumental analysis
Instrumental Analysis
Spectrochemical Analysis
Fundamentals of Molecular
Spectroscopy
作者
D. A. Skoog, et. al.
G. D. Christian , et. al.
J. D. Ingle, Jr. et. al.
C. N. Banwell
& E. M. McCash
出版社
Saunders college (歐亞代理)
Allyn & Bacon Inc.(眾光代理)
Prentice Hall, Inc. .(眾光代理)
The McGraw-Hill (歐亞代理)
兩次考試 50%
期末報告: 50%
平時: ±20%
Chapter 1:
An Introduction to Spectrochemical Analysis
Optical Spectroscopy:
Any means to obtain chemical information by examination of the
variation of the properties of electromagnetic radiation excited
or emitted from matters.
Any forms of the energy can be used to induce the variation of
the properties of electromagnetic radiation, i.e. thermal energy,
particles, electrons, electromagnetic radiations.
1. General properties of electromagnetic radiations
Wave (electromagnetic wave) and Particle (photon)
A. Wave Properties:
a. General
l
A
time
A: amplitude; l: wavelength
v :frequency = c/l
c :speed of radiation
in vacuum, 3x108 m/s
b. Spectrum of Electromagnetic Radiation
3E10
1021
3E8
1019
3E6
3E4
1017
x-ray
g-ray
10-13
1015
Visible
Ultraviolet
10-11
10-9
10-7
3E2
1013
3E0
1011
3E-2
3E-4
109
107
Wavenumber (cm-1)
Frequency (Hz)
101
Wavelength (m)
Microwave
Radio
Infrared
10-5
10-3
10-1
c. Interactions with Matters
X-ray Photo
The UV Camera/Spectrograph
deployed and left on the Moon
by the crew of Apollo 16 took
this picture. The part of the
Earth facing the Sun reflects
much UV light. Even more
interesting is the side facing
away from the Sun. Here,
bands of UV emission are also
apparent. These bands are the
result of aurora caused by
charged particles given off by
the Sun. They spiral towards
the Earth along Earth's
magnetic field lines.
Visible
Near infrared waves are not hot at all
- in fact you cannot even feel them.
These shorter wavelengths are the
ones used by your TV's remote control
Mid infrared waves are thermal. In
other words, we experience this type
of infrared radiation every day in the
form of heat! The heat that we feel
from sunlight, a fire, a radiator or a
warm sidewalk is infrared. The
temperature-sensitive nerve endings
in our skin can detect the difference
between inside body temperature
and outside skin temperature.
This image of a building with a tree and
grass shows how Chlorophyll in plants
reflect near infrared waves along with
visible light waves. Even though we can't
see the infrared waves, they are always
there. The visible light waves drawn on
this picture are green, and the infrared
ones are pale red. This image was
taken with special film that can detect
invisible infrared waves. This is a falsecolor image. False-color infrared images
of the Earth frequently use a color
scheme like the one shown here, where
infrared light is mapped to the visible
color of red. This means that everything
in this image that appears red is giving
off or reflecting infrared light. This makes
vegetation like grasa and trees appear
to be red. The visible light waves drawn
on this picture are green, and the
infrared ones are darker red
This is an image of Phoenix,
Arizona showing the near
infrared data collected by the
Landsat 5 satellite. The light
areas are areas with high
reflectance of near infrared
waves. The dark areas show little
reflectance.
This image shows the infrared data
(appearing as red) composited with
visible light data at the blue and green
wavelengths.
Humans, at normal body temperature,
radiate most strongly in the infrared at
a wavelength of about 10 microns.
This image shows a man holding up a
lighted match!
The image at the left shows a cat in the
infrared. The orange areas are the
warmest and the white-blue areas are
the coldest.
Microwaves have wavelengths that
can be measured in centimeters! The
longer microwaves, those closer to a
foot in length, are the waves which
heat our food in a microwave oven.
Microwaves are good for transmitting
information from one place to another
because microwave energy can
penetrate haze, light rain and snow,
clouds, and smoke.
Shorter microwaves are used in remote
sensing. These microwaves are used
for radar like the doppler radar used in
weather forecasts. Microwaves, used
for radar, are just a few inches long.
Because radar senses electromagnetic waves that are a reflection of an
active transmission, radar is considered an active remote sensing
system. Passive remote sensing refers to the sensing of electromagnetic
waves which did not originate from the satellite or sensor itself. The
sensor is just a passive observer.
Because radio waves are larger than
optical waves, radio telescopes work
differently than telescopes that we use for
visible > light (optical telescopes). Radio
telescopes are dishes made out of
conducting metal that reflect radio waves
to a focus point. Because the wavelengths
of radio light are so large, a radio
telescope must be physically larger than
an optical telescope to be able to make
images of comparable clarity. For example,
the Parkes radio telescope, which has a
dish 64 meters wide, cannot give us any
clearer an image than a small backyard
telescope!
Common spectroscopic methods based on
electromagnetic radiations
Type Spectroscopy
g-ray; emission
l (or v )
Quantum Transition
0.005-1.4 Å
Nuclear
X-ray; absorption,
emission, fluorescence,
diffraction
0.1-100 Å
Inner electron
Vacuum UV; absorption
10-180 nm
Bonding electron
UV/Vis; absorption,
emission, fluorescence
180-780 nm
Bonding electron
Infrared; absorption
(Raman; scattering)
Microwave; absorption
Electron Spin Resonance
(ESR); absorption
Nuclear Magnetic Resonance
(NMR); absorption
780 nm – 300 mm
(1.3x104 – 33 cm-1)
0.75 – 3.75 mm
3 cm
0.6 –10 m
Rotation/vibration
of molecule
Rotation
Spin of electron in
a magnetic field
Spin of nuclei in
a magnetic field
Atom
..
.
2S
1S
Molecule
..
.
v2
v1
..
.
E3
..
.
v3
E2
v2
E1
..
.
R2
R1
v1
c. Mathematical description of a wave
i. Wave function
y = A sin (w t) ; w = 2   (angular velocity);
 : frequency; A: amplitude
l
time
A
y = A sin (w t + ) ;  : phase angle
l
time
A

ii. Superposition
Constructive: w1 = w2 and 1 = 2
y1 = A1 sin (w1 t + 1)
y2 = A2 sin (w2 t + 2)
y = y1 + y2 = A1 sin (w1 t + 1) + A2 sin (w2 t + 2)
Destructive: w1 = w2 and 1 - 2 = 180 o
y1 = A1 sin (w1 t + 1)
y2 = A2 sin (w2 t + 2)
y = y1 + y2 = A1 sin (w1 t + 1) + A2 sin (w2 t + 2)
Periodicity (or beat) : w1  w2
Pb = 1/v
Jean Fourier : Any periodic function can be described
by a sum of simple sine or cosine term
iii. Diffraction of radiation
Slit  l
iv. Reflection of radiation (when n1  n2, it happens)
q1
q2
n1
n2
q1 = q2
at q = 0o;
I r / Io = (n2 - n1)2/(n2+n1)2
v. Refraction of radiation
n1
q1
Snell’s law:
n1sin q1 = n2 sin q2
q2
n2
n1
q1
vi. Transmission of radiation
Air
l= 500 nm
v = 6.0 x 1014 Hz
Glass
l= 330 nm
v = 6.0 x 1014 Hz
Air
l= 500 nm
v = 6.0 x 1014 Hz
Normal dispersion
Vair = vl = 3.00 x 1010 cm/s;
Vglass = vl = 1.96 x 1010 cm/s
n (refractive index)  C/Vglass
n
Anomalous dispersion
IR
UV
vii. Scattering of radiation
Radiation pass through particles, radiation is momentary
retained followed by re-emission of the radiation.
•Rayleigh scattering: particle size  l, Is  1/l4
•Tyndall Effect: Particle can be seen by naked eyes
* Raman Scattering: Momentary Polarized by an intense source
vii. Polarization of radiation
x
Un-polarized
radiation
time
y
Plane Polarized
Radiation
x
y
time
B. Quantum-mechanical Properties of
electromagnetic radiation: Photon or Quanta (量子)
1.
Photoelectric Effect
Hertz, 1887 observation; Einstein,1905 Theory
Millikan, 1916 Theoretical conformation
photon
cathode
e-
By applying negative voltage to the anode
at the point that no current is observed.
This point of voltage is called stopping
voltage (Vs).Observations:
anode
A
V
+
–
i.
Vappl more positive than Vs,
Photocurrent  intensity of Radiation
ii. Vs depends on :
frequency of incident radiation,
chemical composition of the coating
on the cathode
iii. Vs is independent to
the intensity of the incident radiation.
2. Interaction of electromagnetic radiation with matters
i. Absorption
Po
Pi
absorbance
..
.
E3
..
.
E3
E2
E2
..
.
v2
E1
E1
v1
atom
l(UV/Vis)
E = Eelectronic transition
molecule
l(UV/Vis)
E = Eelectronic transition
+ Evibrational transition
+ Erotaional transition
molecule
l(IR)
E = Evibrational transition
+ Erotaional transition
ii. Emission
Intensity
..
.
..
.
E3
E3
E2
E2
..
.
v2
E1
E1
v1
atom
molecule
l(UV/Vis)
E = Eelectronic
transition
l(UV/Vis)
E = Eelectronic transition
+ Evibrational transition
+ Erotaional transition
molecule
l(IR)
E = Evibrational transition
+ Erotaional transition
iii. Relaxation process
(i.e. fluorescence, phosphorescence)
Non-radiative relaxation
{
Excitation
fluorescence, phosphorescence
3. Quantitative aspects of spectrochemical measurements
Detection of power of radiation
S = k x P + kd
;
S: signal (in voltage or current)
P: Power of radiation
k: a proportional constant
kd: dark current
i. Emission, luminescence, and scattering methods
Measuring radiation power directly
Emission of radiation  concentration of matter
P=kxC
 S = k’ x C
P
ii. Absorption methods
Po
Pi
b
Transmittance, T = Pi/Po
% T = Pi/Po x 100%
Absorbance, A = - log10 T
= -log (Pi/Po)
Beer’s Law
A=axbxc
A=xbxc