diff --git a/base_classes/NXelectron_level.nxdl.xml b/base_classes/NXelectron_level.nxdl.xml
index 97ed107ee..702548904 100644
--- a/base_classes/NXelectron_level.nxdl.xml
+++ b/base_classes/NXelectron_level.nxdl.xml
@@ -30,32 +30,42 @@
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://definition.nexusformat.org/nxdl/3.1 ../nxdl.xsd"
>
- TODO ??? levels of electrons in atoms.
+ Electron energy levels in atoms for spectroscopy.
- TODO Name of the atomic orbital in IUPAC or X-ray notation.
+ Electron energy level for spectroscopy in IUPAC notation.
- The corresponding atomic notation *nlj* is also given, where *n* the principal quantum number,
- *l* the orbital angular momentum quantum number (expressed with letters s, p, d, ...) and *j = l + s*
- (*s=±½* the spin quantum number).
+ The corresponding *nlj* notation is also given, where *n* the principal quantum number (shell),
+ *l* the azimuthal quantum number (subshell, expressed with letters *s=0*, *p=1*, *d=2*, ...)
+ and *j = l + s* (*s=±½* the spin quantum number).
- - 1s1/2
- - 2s1/2
+ - 1s
+ - 2s
- 2p1/2
- 2p3/2
- - 3s1/2
+ - 3s
- 3p1/2
- 3p3/2
- 3d3/2
- 3d5/2
- - 4s1/2
+ - 4s
- 4p1/2
- 4p3/2
- 4d3/2
- 4d5/2
- 4f5/2
- 4f7/2
+ - 5s
+ - 5p1/2
+ - 5p3/2
+ - 5d3/2
+ - 5d5/2
+ - 5f5/2
+ - 5f7/2
+ - 6s
+ - 6p1/2
+ - 6p3/2