The basic principle of spectrum analyzer

First, the generation of atomic spectrum Atomic emission spectrometry is based on the spectrum emitted by the atom to determine the chemical composition of the material. Different substances consist of atoms of different elements, and atoms contain a closely packed atomic nucleus surrounded by constantly moving electrons. Each electron is at a certain energy level and has a certain amount of energy. Under normal circumstances, the atom is in a stable state, its energy is the lowest, this state is called the ground state. But when an atom is affected by energy (such as heat energy, electric energy, etc.), the atom acquires energy by colliding with the high-speed movement of gaseous particles and electrons, causing the outer and inner electrons of the atom to jump from the ground state to a higher energy level. The atom in this state is called the excited state. The energy required for an electron to oscillate from a ground state to an excited state is called an excitation potential. When the applied energy is large enough, the electrons in the atom depart from the binding force of the nucleus, making the atom an ion. This process is called ionization. The energy required for an atom to lose one electron to become an ion is called the first ionization potential. The outer electrons in the ion can also be excited, and the required energy is the excitation potential of the corresponding ion. The atoms in the excited state are very unstable, and they jump 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, excess energy is released. This energy radiates in the form of electromagnetic waves of a certain wavelength. The radiated energy can be expressed by the following equation: (1) E2 and E1 are the energies of high and low energy levels, h is the Planck constant, v and λ are the frequency and wavelength of the emitted electromagnetic wave, and c is the speed of light in vacuum.

The wavelength of each emitted line depends on the difference between the two energy levels before and after the transition. Because of the many energy levels of the atoms, after the atoms are excited, their outer layer electrons can have different transitions, but these transitions should follow certain rules (that is, “spectrum selection laws”), and thus a series of atoms can be generated for specific elements. The characteristic spectral lines of different wavelengths, these lines are arranged in a certain order, and maintain a certain intensity ratio. Spectral analysis is to identify the existence of elements (qualitative analysis) by identifying the characteristic spectrum of these elements, and the intensity of these spectral lines is related to the content of the element in the sample. Therefore, the intensity of these lines can be used to determine the elements. Content (quantitative analysis). This is the basic basis for emission spectrum analysis.

Second, the emission spectrum analysis process 1. The sample is evaporated, atomized (transformed into a gaseous atom) under the influence of energy, and the outer electrons of the gaseous atom are excited to a high energy state. When transitioning from a higher energy level to a lower energy level, atoms will release excess energy and emit characteristic lines. This process is called evaporation, atomization, and excitation and needs to be realized by means of an excitation light source.

2. The radiation generated by the atoms is dispersed and dispersed, and recorded on the photosensitive plate in the order of wavelengths, and a regular spectral line, ie, a spectrum, can be presented. It is achieved by means of a spectroscopic instrument's spectroscopic and detection device.

3. Qualitative identification or quantitative analysis was performed based on the spectrum obtained. Since the atomic structures of different elements are different, the wavelengths of the emission line when excited are not the same, ie, each element has its own wavelength, so the presence of the element can be accurately identified based on the characteristic spectrum of these elements. (analysis), and the intensity of these spectral lines is related to the content of the element in the sample, so the intensity of these lines can be used to determine the content of elements (quantitative analysis).