January 1995
Please note the style followed in Physical Review A and Physical Review E for atomic and molecular notation.
Elements are roman:
H, Na, Cl, P, etc.
Superscripts to elements indicate charge states:
Ca2+ (not Ca++)
Ca2+* for an excited ion
Presuperscripts and presubscripts to elements indicate atomic mass and atomic number:
$_{53}^{125}\textrm{I}$
For molecular ions, superscripts and subscripts are staggered:
H3+, He2*, (D2O)n+
Roman numerals following elements are set in small caps with a thin space separating the element and the roman numerals:
Na I
but with a full space in a series:
Na I, II, III
Letters denoting atomic configurations are set italic, with a full space between the element and the state:
Na 3p
(but for a transition there is a thin space between the element and the configuration):
Na 3p – Na 3d
Superscripts to levels indicating odd and even parity are lowercase italic “oh” and “ee”:
$^{1}P_{3/2}^{o},^{1}S _{3/2}^{e}$
Thin spaces are inserted for clarity in the following notation for atomic and molecular levels:
3p3P1/2, 3 2P3/2, A 3Π$_{μ}^{+}$, CO X 1Σ+, He II α
For x rays, the Greek letter is on line:
Kα, Kβ, Lα, Lβ, Cu Kα, Kα1
For spectral lines of hydrogen, the Greek letter is a subscript and roman letters indicate the series:
Balmer series: Hα, Hβ
Lyman series: Ly-α, Ly-β or
Lyman series: Lα, Lβ (Ly-α, Ly-β, Lyman-α, Lyman-β are also acceptable)
Note that italic is printed for shells, edges:
K shell, L shell, K-Auger-electron emission, K edge
The author’s use of parentheses allows notation to be closed up:
2S1/2(F = 1), Br+(3P 2), Ar2+(3s23p4), (3p5 2P )Ar+
Indicate bonds with a “bond” dash:
C — N bond
${∠}$ (H — O — H) = 70◦
Protons, electrons, and neutrons are indicated with lowercase italics:
p, e, and n
Nucleon is spelled out.