Emission
longer
Emitted light has a __________ wavelength than absorbed light.
Relaxation
Losing energy; trying to go to the ground state
do not, ground, conserved
Molecules __________ remain excited (because at some point, does not reach a certain amount of discrete level of energy, so must go down to __________state) - Energy must be __________
Fluorescence
Molecules can lose energy by emitting light in a process called ____________ - does not give off photons
emit, slow
The easiest way for a molecule to dissipate (disappear) excess energy is to _______heat and ________ its vibrations
ground
The energy of photon goes to the ________ state in Fluorescence process
decomposition, dioxane, gernerates
The reaction in glow sticks is driven by the rapid ____________ of the "_________" to carbon dioxide (A+B --> C* + D) which ___________ a lot of energy - breaking off of Carbon and Oxygen (dioxane), ___________more energy
Luminescence
This "relaxation" via emission of light is known generally as _____________
Emission
When molecules of light relax to the ground state, gives off energy.
Bioluminescence
_____________ and Chemilunesene need some chemical reaction that causes light
Luminescence
- Transmission can only be detected directly in line with the incident light. - ___________can be detected in all directions - Emitted wavelengths often dominate the light observed - general term for glowing
emit
After molecules absorb light and become excited, they can _______ light to return to the ground state
reverse, slow
After vibrational relaxation occurs, finally the molecules return to ground state and the molecules must "________their spin" again making this another __________ process.
reverses, intersystem crossing, slowly
Alternatively, one of the electrons in the molecule "__________ its spin" causing a slight change in energy in _________________ stage - This is very hard and therefore occurs very __________
Bioluminescence, luciferase
Defined as the emission of light as a result of a biological reaction - ex. Firefly Luciferin ---Luciferin + O2 ---> Oxyluciferin + yellow light ---The reaction is catalyzed by an enzyme called ___________ ---The light emission step is very similar to that in a glow stick! ---The light emission step again involves the rapid release of CO2 and generation of energy - another ex. Crystal jellyfish
Chemilumenscence
Defined as the emission of light due to a chemical reaction. - A and B react to form an excited product C, then C relaxes to ground state. Because the product C has a different energy from the reactants, A and B, energy is emitted as light --- so as reaction starts, relaxation emits light (giving off energy), which creates a glow (or luminescence) - ex. glow sticks (must explain this) - light is given off not heat!
Phosperescence
Fluorescence and ____________ need light to see excitation
longer, rapidly
Fluorescence occurs when while the light source is present to excite molecules. - Giving off ________ wavelengths of light - Shut off the light, don't see it, it's over - happens easily and ____________
Emission follows absorption
How does emission happen?
bluer
If you cannot differentiate the ripeness by the color of the banana (cause you are blind) use your feel, sense of smell to figure it out. - since Fruit bats are colorblind and bananas absorb UV light and give off blue light, can detect if the banana is ripe by looking at the blue light. - the _________they are, the riper they are
Fluorescence
__________________ occurs when while the light source is present to excite molecules - ex. glow-in-the-dark-stickers - if you dissolve fluorescein in water and put it under black light, will look green (absorbs cyan, observes orange/red) - since tonic water contains quinine, if you put a UV light over it, it glows
no light
____________is emitted during a vibrational relaxation