Energy spectrum analysis
2018-07-23 11:28:30 SUSHI GUANGBO TEST TECHNOLOGY CO.,LTD 已读
Energy spectrum analysis
The main difference between spectral analysis and energy spectrum analysis
The former refers to the effect of the spectrum on the research object; the latter refers to the effect of energy on the research object.
Spectral analysis: A method for identifying a substance based on its spectrum and determining its chemical composition and relative content is called spectral analysis. Its advantages are sensitive and rapid. Historically, many new elements have been discovered through spectral analysis, such as 铷, 铯, 氦, etc. According to the analysis principle, spectral analysis can be divided into two types: emission spectrum analysis and absorption spectrum analysis; according to the shape of the measured components, it can be divided into atomic spectrum analysis and molecular spectrum analysis. The measured component of the spectral analysis is called the atomic spectrum of the atom, and the molecular component of the measured component is called the molecular spectrum.
The emission spectrum analysis is based on the intensity of the characteristic spectrum of the atom or molecule being emitted in an excited state.
The absorption spectrum is calculated based on the characteristic spectrum of the element to be tested, by the intensity of the weakened intensity after the ground state atom of the element to be tested in the sample vapor absorbs the spectrum of the element to be measured. It complies with Langper-Beer's law:
A= -lg I/I o= -lgT = KCL
Where I is the transmitted light intensity, I0 is the emitted light intensity, T is the transmittance, and L is the light passing through the atomizer optical path since L is a constant value so A = KC.
The atoms of any element are composed of nuclei and electrons moving around the nucleus. The electrons outside the nucleus are layered according to the level of their energy to form different energy levels. Therefore, a nucleus can have multiple energy levels.
The lowest energy level is called the ground state level (E0 = 0), the other energy level is called the excited state level, and the lowest excited state is called the first excited state. Under normal conditions, the atoms are in the ground state, and the extranuclear electrons move in the orbit with the lowest energy.
If a certain external energy, such as light energy, is supplied to the ground state atom, when the external light energy E is exactly equal to the energy level difference E between the ground state and a higher energy level in the ground state atom, the atom will absorb light of this characteristic wavelength. The outer electrons transition from the ground state to the corresponding excited state. The original energy-providing light lacks some characteristic spectral lines in the spectral line after splitting, thus generating an atomic absorption spectrum.
Energy spectrum analysis: The principle of photoelectric effect is used to measure the kinetic energy of photoelectrons emitted from a sample by monochromatic radiation (and thereby determine its binding energy), the photoelectron intensity and the angular distribution of these electrons, and apply this information to study atoms and molecules. The technique of condensing phases, especially the electronic structure of solid surfaces. For solids, photoelectron spectroscopy is a surface sensitive technique. Although the incident photons can penetrate deep into the solid, only the photoelectrons in a thin layer of 20-30 Å below the solid surface can escape (the average free path of inelastic scattering of photons is 10-10 times larger than that of electrons), Therefore, the spectrum reflects the information of the solid surface.
Metallographic analysis (microstructure, metallurgical quality, forming process, heat treatment process analysis)
Fracture analysis (fracture macroscopic morphology, fracture microstructure, fracture form, fracture mechanism, fracture cause analysis)
Component analysis (material qualitative and quantitative analysis)
Mechanical properties analysis (tensile strength, elongation, hardness, etc.)