Basic principle of spectrum analyzer

Basic principle of spectrum analyzer

I. generation of atomic spectrum

atomic emission spectrum analysis is based on or will use ceramic materials on S3 to determine the chemical components of substances according to the spectrum emitted by atoms. Different substances are composed of atoms of different elements, and atoms contain a closely structured nucleus surrounded by moving electrons. Each electron is at a certain energy level and has a certain energy. Under normal circumstances, the atom is in a stable state with the lowest energy. This state is called the ground state. However, when the atom is affected by energy (such as thermal energy, electric energy, etc.) with a total investment of 3 billion yuan, the atom obtains energy due to the collision with high-speed gaseous particles and electrons, making the electrons in the middle and outer layers of the atom from 3.5 billion yuan The zigzag process requires the transition of the ground state to a higher energy level in a stable motion. The atom in this state is called an excited state. The energy required for the electron to transition from the ground state to the excited state is called the excitation potential. When the applied energy is large enough, the electrons in the atom break away from the binding force of the nucleus and make the atom become ions. This process is called ionization. The energy required for an atom to lose an electron and become an ion is called the first-order ionization potential. The outer electrons in the ion can also be excited, and the energy required is the excitation potential of the corresponding ion. The atom in the excited state is very unstable and will transition to the ground state or other lower energy levels in a very short time

when an atom transitions from a higher energy level to a ground state or other lower energy level, it will release excess energy, which is radiated in the form of electromagnetic waves with a certain wavelength. The radiated energy can be expressed as follows: (1) E2 and E1 are the energy of high energy level and low energy level respectively, and H is Planck constant; V and λ Are the frequency and wavelength of the emitted electromagnetic wave respectively, and C is the speed of light in vacuum

the wavelength of each emitted spectral line depends on the difference between the two energy levels before and after the transition. Due to the many energy levels of the atom, the outer electrons of the atom can have different transitions after being excited, but these transitions should follow certain rules (i.e. "spectral selection law"), so a series of characteristic spectral lines with different wavelengths can be generated for the atoms of specific elements, which are arranged in a certain order and maintain a certain intensity ratio. Spectral analysis is to identify the existence of elements from the characteristic spectra of these elements (qualitative analysis), and the intensity of these spectral lines is related to the content of the element in the sample. Therefore, the intensity of these spectral lines can be used to determine the content of elements (quantitative analysis). This is the basic basis of emission spectrum analysis

II. Process of emission spectrum analysis

1. Evaporate and atomize the sample under the action of energy (convert it into gaseous atom), and excite the outer electrons of gaseous atom to high energy state. When the transition from a higher energy level to a lower energy level, the atom will release excess energy and emit characteristic spectral lines. This process is called evaporation, atomization and excitation, and needs to be realized with the help of excitation light source

2. The radiation produced by the atom is dispersive and recorded on the photosensitive plate according to the wavelength order, and the regular spectral lines, i.e. spectrogram, can be presented. It is realized by means of the spectroscopic and detection device of the spectrograph

3. Qualitative identification or quantitative analysis according to the obtained spectrum. Due to the different atomic structures of different elements, when excited, the wavelengths of emission spectral lines are different, that is, each element has its characteristic wavelength. Therefore, according to the characteristic spectra of these elements, the existence of elements can be accurately identified (qualitative analysis), and the intensity of these spectral lines is related to the content of the element in the sample. Therefore, the intensity of these spectral lines can be used to determine the content of elements (quantitative analysis). (end)