,TOPIC ONE : COLOURS 13 CHROMOPHORE S
Precept ion of colour
↳
white light consist of all colours
↳ colours ( wavelengths) we observe
of
is the visible light region
the electromagnetic spectrum
subtractive colour Model
that is not
•
Colour is absorbed
subtracted
"
reflected
"
→
light perceived
'
reflected is
as complement of the
absorbed colour
BLACK All colours absorbed WHITE absorbed
nothing
=
=
MONOCHROMATIC LIGHT
↳
of wavelength
Light compromising one colour or
↳
If ABSORBED =
Dimmer colour
↳ If REFLECTED =
Bright colour
,Measuring Colour Absorption
wavelengths of colour
↳
molecules absorbs certain
↳ measured by UV Visible absorption spectroscopy
-
① Monochrome ter diffracts the light source
② Light split into reference and incident beam
into two equal beams
③ sample absorbs certain wavelengths ,
remaining transmitted
④ Intensity of transmitted beam is dimmer than reference
⑤ Intensity difference between two beams measured to
determine amount of light absorption
chromophore s
structural feature possessed by
'
a molecules
functional of light
'
molecules that absorb
groups or
parts
charged groups
↳
polar or
Have extended
f¥k#r
'
conjugation
connected systems
pi
↳
, Photo Processes
physical
Molecular Orbital Theory
↳
two atomic orbitals to make molecular orbitals
sp )
> }
( sp ,
sp ,
↳
Lowest MO filled first
energy
-
orbital LOW ENERGY more stable Nt ~
Bonding
= /
t Anti -
Bonding orbital = HIGH ENERGY ,
less stable wt w
node
↳
Lowest -
energy MO
that doesnta LUMO →
LUMO is Lowest unoccupied
molecular orbitals
Highest
↳
MO
energy
-
with one or more e-
HOMO is
Highetcpied HOMO →
molecular orbital
of
Absorption Light
-
when a molecule absorbs light , an electron is excited
from HOMO to LUMO
-
HOMO are electrons in orbitals of IT systems
p
-
HOMO
wmo
§
Precept ion of colour
↳
white light consist of all colours
↳ colours ( wavelengths) we observe
of
is the visible light region
the electromagnetic spectrum
subtractive colour Model
that is not
•
Colour is absorbed
subtracted
"
reflected
"
→
light perceived
'
reflected is
as complement of the
absorbed colour
BLACK All colours absorbed WHITE absorbed
nothing
=
=
MONOCHROMATIC LIGHT
↳
of wavelength
Light compromising one colour or
↳
If ABSORBED =
Dimmer colour
↳ If REFLECTED =
Bright colour
,Measuring Colour Absorption
wavelengths of colour
↳
molecules absorbs certain
↳ measured by UV Visible absorption spectroscopy
-
① Monochrome ter diffracts the light source
② Light split into reference and incident beam
into two equal beams
③ sample absorbs certain wavelengths ,
remaining transmitted
④ Intensity of transmitted beam is dimmer than reference
⑤ Intensity difference between two beams measured to
determine amount of light absorption
chromophore s
structural feature possessed by
'
a molecules
functional of light
'
molecules that absorb
groups or
parts
charged groups
↳
polar or
Have extended
f¥k#r
'
conjugation
connected systems
pi
↳
, Photo Processes
physical
Molecular Orbital Theory
↳
two atomic orbitals to make molecular orbitals
sp )
> }
( sp ,
sp ,
↳
Lowest MO filled first
energy
-
orbital LOW ENERGY more stable Nt ~
Bonding
= /
t Anti -
Bonding orbital = HIGH ENERGY ,
less stable wt w
node
↳
Lowest -
energy MO
that doesnta LUMO →
LUMO is Lowest unoccupied
molecular orbitals
Highest
↳
MO
energy
-
with one or more e-
HOMO is
Highetcpied HOMO →
molecular orbital
of
Absorption Light
-
when a molecule absorbs light , an electron is excited
from HOMO to LUMO
-
HOMO are electrons in orbitals of IT systems
p
-
HOMO
wmo
§
