Atomic and nuclear properties of liquid hydrogen (H2)
QuantityValueUnits ValueUnits
Atomic number 1     
Atomic mass 1.008(7) g mole-1   
Specific gravity 0.07080 g cm-3   
Mean excitation energy 21.8 eV   
Minimum ionization 4.034 MeV g-1cm2 0.2856 MeV cm-1
Nuclear collision length 42.8 g cm-2 605.1 cm
Nuclear interaction length 52.0 g cm-2 734.6 cm
Pion collision length 70.4 g cm-2 994.5 cm
Pion interaction length 80.3 g cm-2 1134. cm
Radiation length 63.05 g cm-2 890.5 cm
Critical energy 278.03 MeV (for e-) 271.52 MeV (for e+)
Molière radius 4.81 g cm-2 67.92 cm
Plasma energy ωp 7.64 eV   
Muon critical energy 3102. GeV   
Melting point 13.81 K -259.3 C
Boiling point @ 1 atm 20.28 K -252.9 C
Index of refraction (Na D) 1.112     
For muons, dE/dx = a(E) + b(E) E. Tables of b(E): PDF TEXT
Table of muon dE/dx and Range: PDF TEXT
Explanation of some entries
Table of isotopes Warning: may not be current
x ray mass attenuation coefficients