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The units used in the eFF .cfg input and .eff output files are given in Table 1.3. An atomic time unit (atu) equals

$\displaystyle \frac{\hbar}{E_{h}} \cdot \sqrt{\frac{\mathrm{amu}}{m_{e}}} = 1.03275 \times 10^{-15}\ \mathrm{seconds}

which is close to 1 fs.

Table 1.3: Units used in eFF input and output files.
Quantity Unit
Energy hartrees
Mass atomic mass units
Time femtoseconds
Positions bohr
Velocities bohr/atu
Forces amu $ \mathrm{bohr^{2}}$/atu = hartrees$ \cdot$bohr
Dipole moment Debye
Temperature Kelvin
Pressure gigapascals
Electric field volt/cm
Electric field frequency Hertz
Electric field wave packet duration femtoseconds

Julius 2008-04-29