

















Study with the several resources on Docsity
Earn points by helping other students or get them with a premium plan
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
Community
Ask the community for help and clear up your study doubts
Discover the best universities in your country according to Docsity users
Free resources
Download our free guides on studying techniques, anxiety management strategies, and thesis advice from Docsity tutors
Indicator Electrodes, Potentiometry, Electrochemistry, Electrode Kinetics, Electrogravimetry, Polarography, Square Wave Voltammetry, Wavelength Selection, Types of Spectroscopy, Detectors, Theory of Molecular Absorption, Absorption by Organic Molecules, Applying UV-vis Spectroscopy are major topics of this course. Main points from these slides are: Molecular Spectroscopy, Spectroscopy, Electromagnetic Radiation, Refractive Index, Wavelength, Speed of Light, Polarizability, Refractive Indices, Re
Typology: Slides
1 / 25
This page cannot be seen from the preview
Don't miss anything!
Molecular Spectroscopy
Spectroscopy
(^) = methods based on the
(EM) and matterinteraction of electromagnetic radiation
Electromagnetic Radiation = form of energy with both wave and particle properties
EM moves through space as a wave
terms of electric vectorbest understood inEM with matter are Most interactions of
Dispersion CurveA Typical
showing
(^) η (^) as
frequencya function of
(^) ν
( νννν )
(η)
Normally
(^) η (^) increases with
(^) ν (^) and this is
referred to as “Normal Dispersion”
When absorption occurs, the nature of the interaction changes
η slows downelectric vector interacts with the medium &^ is a measure of the extent to which the
For a given frequency and medium, a larger η (^) means more interaction with electric field
polarizability & the medium is said to have greater
(^) i.e., is more able to follow
the electric vector
Dispersion CurveA Typical η 2) regions where ν increases with absorbtion bandprior to an
This is referred to as normal dispersion
( νννν )
(η)
Dispersion CurveA Typical η 3) regions where ν decreases with absorption bandsvery sharply at
because the nature of the interaction changesThis is referred to as anomalous dispersion
( νννν )
(η)
Refractive indices (
η ) for various substances at
589 nm (the sodium D line)
Substance
η
air
water, 20
(^) o C
NaCl crystal
benzene
quartz (fused)
glass (crown)
ethyl alcohol
carbon disulfide
Refraction
(^) = change in velocity of EM as it
goes from one medium to another
to surfaceNormal
Velocity largerMedium 1 (air)
(^) η (^) = 1.
Velocity smallerMedium 2 (glass)
(^) η (^) = 1.
rayIncident
Ф 1 Ф 2
ray Refracted
directionOriginal
normalRay bent toward
Critical Angle
C )
to surface Normal
Medium 2 (glass)Medium 1 (air)
90 ray isIncident o to
grazing incidencethis is callednormal
Ф 1 Ф 2
ray Refracted
Maximum value of
(^) Ф 2
Ф (^2) = (^) Ф C At 90
o incidence sin
(^) Ф (^1) = 1.
η 1
sin (^) Ф C = ----- η 2
(^) ν (^) but can be out of
phase (i.e., they start in different places)
(^1) +y
2 formed by adding y
1 & y
2 by
vector addition
Interference
(^) - amplitude of the resulting
wave depends on phase difference
(^) α (^1)
α 2
⇒Interference Constructive waves add
Destructive Interference
(^) ⇒
(^) waves cancel
At (^) α (^1)
α (^2) = 0
o adding of waves gives
Maximum Constructive Interference
(^0) o
180 o 360 o 540 o 720 o 900 o
is zeroWave 1 & Wave 2difference betweenPhase angleResultant waveWave 2Wave 1
(^) α (^1)
α (^2) = 0 o
Amplitude
docsity.co
When
(^) α (^1)
α (^2) = 180
o or 540
o adding of waves
gives Maximum Destructive Interference
(^0) o
180 o 360 o 540 o 720 o 900 o
Resultant waveWave 2 Wave 1
is 180Wave 1 & Wave 2difference betweenPhase angle
o (α (^1)
α (^2) = 180
)o
Amplitude
docsity.co
Fourier Analysis
(^) – mathematical process of
various component frequencies.and a computer to figure out amplitudes ofNMR. Requires complex mathematicsTransform (FT) methods like FTIR and FTintegral and is important in all Fourierfrequencies. This requires a Fouriervarious frequencies into their individualresolving a combination of waves of