HI shows the volumetric concentration of hydrogen atoms in the substance normalized to the volumetric hydrogen concentration of water in standard conditions:
| HI = \frac{9 \, n_H \, A_H}{\sum_i n_i \, A_i} \cdot \rho_B |
where
\rho_B | rock density |
|---|---|
n_H | number of hydrogen atoms in molecule |
A_H | atomic mass of hydrogen in molecule |
n_i | number of i-th type of atoms in molecule |
A_i | atomic mass of i-th type of atoms in molecule |
For water in standard condition is HI =1.