The obtained values are in good agreement with quantum mechanical estimates of the equilibrium fractionation and classic kinetic fractionation as well as with results from other light three-isotope systems (oxygen, magnesium, silicon and sulfur).While the value of the fractionation ratio varies with the relative importance of kinetic and equilibrium fractionation, the values obtained in the present study cluster around b = 1.9.The ratio is measured using an ordinary mass spectrometer.The isotopic composition of the sample being measured is expressed as delta13C which represents the parts per thousand difference (per mille) between the sample carbon 13 content and the content of the international PDB standard carbonate (Keith et al., 1964; Aitken, 1990).
Photosynthesis incorporates 14C into plants and therefore animals that eat the plants.
The half-life is the time taken for an amount of a radioactive isotope to decay to half its original value.
Because this decay is constant it can be used as a “clock” to measure elapsed time assuming the starting amount is known.
C ratios and this value has been applied by the radiocarbon community ever since.
While theoretical considerations suggest moderate deviations of b from 2.0, some measurements have suggested larger differences (e.g. With the high precision attained in radiocarbon measurements today (±2‰), even a relatively small deviation of b from 2.0 can impact the accuracy of radiocarbon data, and it is, therefore, of interest to re-evaluate the fractionation corrections.