[skip navigation]
[ASD Home][Lines Query][Levels Query][List of Spectra][Ground States and Ionization Energies][Bibliography][Help] NIST Physical Measurement Laboratory
National Institute of Standards and Technology NIST Physical Measurement Laboratory

NIST Atomic Spectra Database Lines Form

 Best viewed with the latest versions of Web browsers and JavaScript enabled
Main Parameters Spectrum e.g., Fe I or Na;Mg; Al or mg i-iii or 198Hg I
Search for   Lower:
Upper: 		 nm
 nm
Output Wavelength Units:

Can you please provide some feedback to improve our database?

Advanced Output Options
Additional Criteria
Format output: Lines:
 All
Only with transition probabilities
Only with energy level classifications
Only with observed wavelengths or intensities
Only with diagnostics
Include Ritz wavelengths for all possible E1 transitions

Include diagnostics data
No JavaScript
No spaces in values
Energy Level Units:
Display output: Bibliographic
Information: 		TP references, Line references
Page size:

Wavelength Data: Observed
Ritz
Observed - Ritz (difference)
Wavenumber (in cm-1)
Uncertainties
Output ordering:
 Wavelength
Multiplet

Optional Search Criteria
Maximum lower level energy: (e.g., 100000)
Wavelength in:
 Vacuum (< 200 nm)   Air (200 - 1,000 nm)  Wavenumber (> 1,000 nm)
 Vacuum (< 1,000 nm)  Wavenumber (> 1,000 nm)
 Vacuum (< 200 nm)   Air (200 - 2,000 nm)   Vacuum (> 2,000 nm)
 Vacuum (all wavelengths)
 Vacuum (< 185 nm)   Air (> 185 nm)
Maximum upper level energy: (e.g., 400000)

Transition strength bounds will apply to:
Minimum transition strength: (e.g., 1.2e+05) Transition strength: Aki   gkAki   in units of 108 s-1
fik     Sik     log(gf)
Relative Intensity
Maximum transition strength: (e.g., 2.5e+12)

 
Transition Type: Allowed (E1)    Forbidden (M1,E2,...)
Accuracy minimum:   (e.g., C+)
Relative intensity minimum: (e.g., 1.2e-03) Level information:
 Configurations  Terms  Energies  J  g
Relative intensities are source dependent and typically are useful only as guidelines for low density sources.
The transition probability, or Einstein coefficient, has units of s-1. Typical values for strong lines are of the order of 108 for neutral atoms and rapidly increase for ions.
The oscillator strength is a dimensionless quantity which for strong lines (both in atoms and in ions) is of the order of unity.
The line strength is proportional to Aki or fik. This parameter does not depend on the transition energy.
The multiplet-averaged lines are shown only if all components of the multiplet are available. Both observed and Ritz values are always presented if any.
Examples of allowed spectra:
Ar I
Mg I-IV
All spectra
Fe I; Si IX,XI; Ni Co-like
H-Ar I-II
Mg Li-like; Al Li-like-Be-like
Sc-Fe K-like-Ca-like
198Hg I
No plots in the output.
If LTE spectrum generation is chosen, the output wavelengths are given.
Values like '1' or '1P' are allowed to select only specific groups of terms.
Selecting this option would generate spectral lines distribution for one or several ions. All lines within a specific ion stage are given the same intensity in order to indicate their positions. The links to the plots will be provided below the final line output.
Selecting this option generates a PNG plot of either relative intensities for observed lines or gA-values for Ritz lines vs. the wavelengths in the visible spectrum. Accordingly, the lower and upper wavelength limits must be not smaller than 380 nm and not larger than 780 nm, respectively.
The links to the plots will be provided below the final line output.
The estimated accuracies for transition probabilities are:
AA: ≤ 1%
A+: ≤ 2% | A: ≤ 3%
B+: ≤ 7% | B: ≤ 10%
C+: ≤ 18% | C: ≤ 25%
D+: ≤ 40% | D: ≤ 50%
E: > 50%
The level populations are calculated according to the Boltzmann distribution within each ion and Saha distribution between the ion stages. Thus, to calculate the spectrum from a single ion, e.g., C I, only Te is required, while for the spectrum from several ions of the same element (e.g., C I-V), Ne must be defined as well. The links to the generated plots and the table of line intensities will be provided below the final line output.
Relative intensity is calculated in the synthetic spectra on an arbitrary scale. This scale can be proportional to energy flux or photon counts per a wavelength interval.
Example: 3.5e22
Example: 150
The Saha-LTE spectrum is calculated with finite Doppler line widths determined by ion temperature.
Ion temperature determines Doppler line widths for the Saha-LTE spectrum. If blank, it is assumed same as electron temperature.