1What types of interferences can occur in AAS?
non-spectral and spectral
2Fluorescence occurence
A molecule must absorb a photon and be promoted from its ground state to an excited vibrational state in a higher electronic state
3Phosphorescence
When a molecule moves from an excited triplet state back to the ground state
4What two things must occur in order for IR absorbance to happen?
1. There must be a change in dipole
2. If the frequency of the radiation matches the natural frequency of the vibration, the IR photon is absorbed and the amplitude of the vibration increases
5Selection rules for IR
-There are different vibrational modes
-Active molecules have a change in dipole
-There's an excitation of molecule to excited vibrational state
-Active molecules have asymmetric stretching/vibrations
6Selection rules for Raman
-There are different vibrational modes
-Active molecules have a change in polarizability
-Momentary distortion of electrons distributed around the bond
-Active molecules have symmetric stretching/vibrations
7Define the term environment for a molecule
Molecular arrangement existing around a given proton
8What is shielding
Protects nucleus from effects of magnetic field
9What is used to protect the magnet in NMR from the outer enviroment?
Liquid N2 and liquid He
10What are three types of scattering?
1. Rayleigh
2. Stokes
3. Anti-stokes
11Rayleigh
Scattered radiation that has the same frequency as source of the radiation, elastic collisions between the photons and molecules in the sample
12Stokes
Photons scattered with less energy than initial
13Anti-stokes
Photons scattered with more energy than initial
14Define NMR
Nuclear Magnetic Resonance
15Define AAS
Atomic Absorption Spectrometry
16Spectral
causes amount of light absorbed to be too high due to species other than analyte
17Non-spectral
affects the formation of analyte free atoms
18AAS
the absorption of discrete wavelengths of light by ground state gas phase free atoms
19NMR
the absorption of radio waves by nuclei of some combined atoms in a molecule that is in magnetic field
20What is the laser for fluorescence used for?
To excite molecules, causing them to emit light, enabling the detection and analysis of specific species
21Virtual State
imaginary state between ground and excited state
22What are the radiation sources of AAS
HCL (hallow cathode light) and EDL (electrodeless discharge lamp)
23What are the atomizer sources
flame and graphite furnace
24What are the detectors for AAS
PMT, PDA, and CCD
25What is the atomization process
Nebulization, Desolation, Liquefaction, Vaporization, Atomization, Excitation, and Ionization
26The 3 regions of the flame
Primary, secondary, and interzonal
27Why do you need two gases
One is acting as the flame and the other is acting as the oxidant
28What are the common fuels
H2, Acetylene, and Propane
29What are the common oxidants
Air and nitrous oxide
30Is the flame better or is the graphite furnace better
Graphite furnace
31Types of non-spectral
chemical, matrix, and ionization
32What type of calibration works for AAS
External or method of standard addition