What does spectral line broadening mean, and an introduction to spectral line width

Line broadening is the difference between two wavelengths corresponding to half of the maximum intensity of a spectral curve, defined as the width of the lines of the spectrum, also known as the half width.

The half-width of the emission spectrum is used to measure the degree of narrowness of the line width of the emission spectrum. Line Broadening Measurements The experiment measures the half-height and full width of the line. Therefore, the spectral line type was analyzed, and the line type was determined to be the VOIGT line type, and then the line type was used to fit the experimental image, and finally the line width was calculated.

Change the number of theoretical plates in the dynamics.

and theoretical plate height. Ideally, the plate height is reduced with increasing column lengths to increase flow rates and reduce analysis time. In general, a carrier gas velocity close to the optimal flow rate can be used, and a column with a small inner meridian can be used.

The packing material used in the packed column should be fine-grained, uniformly particles, and evenly packed to reduce vortex diffusion and improve column efficiency.

Change the capacity factor of the stationary phase and the mobile phase to improve resolution.

Increasing the volume factor within a certain range can effectively improve the resolution, but when the volume factor is greater than 5, the resolution changes very little, but the retention time increases rapidly. At this time, measures such as reducing the column temperature and reducing the carrier gas velocity can be taken.

Is it to add spectral lines up and down on top of the basic spectral lines?

The spectral lines are not monochromatic and infinitely narrow, but have a certain width and outline. Generally, the wavelength range corresponding to the intensity drop to half the maximum value is called the spectral line width, which is denoted by δ. The causes of the change of spectral line width include thermal broadening, pressure broadening, electric or magnetic field broadening, and self-priming broadening.

Due to its own physical properties or the influence of the physical state of the environment, the spectral lines emitted or absorbed by atoms become spectral lines that are not a single frequency. In some cases, the lines are not only broadened, but also shifted. The spectrum of the spectrum buried by the physical properties of the radiated atom itself includes the natural width of the spectrum and the Doppler broadening.

The former arises from the fact that the atom has a certain lifetime at the excitation energy level in which it is located; The latter results from the random thermal movement of radiation atoms.

spectral line broadening

The phenomenon of broadening of the spectral lines caused by the influence of the physical state of the environment in which the luminescent atoms are located. There are two main types: Doppler broadening.

In fact, the luminescent atoms move randomly, and the light waves emitted by the moving atoms produce a Doppler frequency shift, and the magnitude of the frequency shift depends on the component of the atom's motion velocity along the observed direction. The magnitude of the luminescence frequency shift of atoms with different velocity components is different. The total effect of the superposition results in a Doppler widening of the spectral lines, the value of which is proportional to the square root of the absolute temperature. Usually the Doppler width is 2 to 3 orders of magnitude larger than the natural width.

Compression-induced broadening. The interaction between the numerous light-emitting atoms in the light source interferes with the luminescence process of the atoms, resulting in the widening of the spectral lines, or the collision with each other to block the luminescence of the atoms, or the Stark effect of the electric field of charged ions on the luminescent atoms, and the widening is related to the number density of the atoms, or the pressure, so it is called pressure-induced broadening. The broadening of spectral lines obscures the details of the spectral structure, so an important part of spectral experimental research is to eliminate the broadening factor of spectral lines. In turn, the broadening of the spectral lines can be used to determine the temperature and pressure in the luminescent gas, and to study the physical processes that occur in it.

In celestial bodies, atmospheres and all other light sources, the radiating atoms are in atomic gases or ionized gases, and the emission spectral lines of the radiating atoms are broadened and shifted due to the constant interaction between various particles (including neutral atoms, ions and electrons).