Atomic and nuclear properties of materials:
Methane (CH4)
QuantityValueUnits ValueUnits
<Z/A> 0.62334     
Specific gravity (20° C, 1 atm) 6.67E-04 g cm-3   
Mean excitation energy 41.7 eV   
Minimum ionization 2.417 MeV g-1cm2 1.613E-03 MeV cm-1
Nuclear collision length 54.0 g cm-2 8.096E+04 cm
Nuclear interaction length 73.8 g cm-2 1.106E+05 cm
Pion collision length 81.8 g cm-2 1.226E+05 cm
Pion interaction length 105.4 g cm-2 1.580E+05 cm
Radiation length 46.47 g cm-2 6.965E+04 cm
Critical energy 146.86 MeV (for e-) 143.82 MeV (for e+)
Molière radius 6.71 g cm-2 1.006E+04 cm
Plasma energy 0.59 eV   
Muon critical energy 1716. GeV   
Melting point 90.68 K -182.5 C
Boiling point @ 1 atm 111.7 K -161.5 C
Index of refraction (@ STP, Na D) 444. (n-1)x106     
Composition:
Elem ZAtomic frac* Mass frac*
H
1
4.00
0.251306
C
6
1.00
0.748694
* 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