The use of density functional theory helps in estimating energy barriers for He to overcome as it diffuses across various crystallographic directions.
[4] Traditional U–Th/He thermochronometry determines the temperature Tc that the analyzed sample had at a time in the past corresponding to the age given by its content of parent and daughter nuclides.
This method is superior in two ways: diffusion kinetics for 4He can be precisely determined and the 4He distribution provides a continuous path in a time-temperature history s opposed to a single point in a bulk-grain date.
[5] More specifically, the 4He distribution in a grain is a function of the time-integrated internal production from parent nuclides, minus diffusion loss and alpha ejection.
[7] The assumptions made in the creationist arguments neglect the sensitivity that He diffusion methods have in regard to temperature fluctuations over time – especially since the granodiorite analyzed in the study has very complex geologic and thermal history.