Atomic and nuclear properties of materials:
Air (dry, 1 atm)
QuantityValueUnits ValueUnits
<Z/A> 0.49919     
Specific gravity (20° C, 1 atm) 1.20E-03 g cm-3   
Mean excitation energy 85.7 eV   
Minimum ionization 1.815 MeV g-1cm2 2.187E-03 MeV cm-1
Nuclear collision length 61.3 g cm-2 5.088E+04 cm
Nuclear interaction length 90.1 g cm-2 7.477E+04 cm
Pion collision length 88.5 g cm-2 7.348E+04 cm
Pion interaction length 122.0 g cm-2 1.013E+05 cm
Radiation length 36.62 g cm-2 3.039E+04 cm
Critical energy 87.92 MeV (for e-) 85.96 MeV (for e+)
Molière radius 8.83 g cm-2 7330. cm
Plasma energy 0.71 eV   
Muon critical energy 1115. GeV   
Boiling point @ 1 atm 78.80 K -194.4 C
Index of refraction (@ STP, Na D) 172. (n-1)x106     
Composition:
Elem ZAtomic frac* Mass frac*
C
6
0.00
0.000124
N
7
0.00
0.755267
O
8
0.00
0.231781
Ar
18
0.00
0.012827
* calculated from mass fraction data.

Explanation of some entries
For muons, dE/dx = a(E) + b(E) E. Tables of b(E): PS PDF TEXT
Table of muon dE/dx and Range: PS PDF TEXT