GET /energy1.pl
nist.gov:nist-atomic-spectra-database-api
Summary: Get energy levels for an atomic spectrum
Operation ID: getEnergyLevels
Auth: unknown
Operation ID: getEnergyLevels
Auth: unknown
Description
Retrieves energy level data for a specified atomic spectrum (element + ionization state). Returns HTML with energy level information including configuration, term, J values, and energies.
Parameters (4)
format
(integer, query, optional, default: 0)
Output format (0=HTML, 1=ASCII text, 2=BibTeX)
Constraints: {'enum': [0, 1, 2]}
output
(integer, query, optional, default: 0)
Output type (0=energy levels only, 1=with transitions)
Constraints: {'enum': [0, 1]}
spectrum
(string, query, required)
Atomic spectrum specification (element symbol + Roman numeral ionization state, e.g., 'H I', 'He II', 'Fe I-III')
units
(integer, query, optional, default: 0)
Energy units for output (0=cm-1, 1=eV, 2=Rydberg, 3=Hartree)
Constraints: {'enum': [0, 1, 2, 3]}
Examples (2)
| Title | Type | URL | Action |
|---|---|---|---|
| Get energy levels for an atomic spectrum | openapi-spec |
https://physics.nist.gov/cgi-bin/ASD/energy1.pl?spectrum=H I |
|
| Get energy levels for an atomic spectrum | probe-gate |
https://physics.nist.gov/cgi-bin/ASD/energy1.pl?spectrum=H+I&units=0&format=0&output=0 |
Probe History
Status Codes
| Time | Status | Latency | Size |
|---|---|---|---|
| 2026-03-23 10:33:44.354791 | 200 | 681ms | |
| 2026-03-23 10:28:56.246607 | 200 | 554ms |
Response Changes
| When | Old | New |
|---|---|---|
| 2026-03-23 10:33:44.354791 | d045b8a4ea7e |
17896fabed0e |