Differences

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--- units [2013/03/01 08:25] – daniel
+++ units [2018/01/05 10:07] (current) – daniel
@@ Line 3: / Line 3: @@
 //potfit// does not need a particular system of units. It can work with any system. The units used by //potfit// are implicitly defined in the configuration and potential files, and possibly by certain parameters specifying the potential.
-The reference configuration file contains atom positions, which implicitly defines a length unit. The interaction potential implicitly makes use of a length unit and an energy unit. Of course, this length unit must be the same as for the configuration file. The two units of length, and energy determine other units - like force and pressure - which are derived from them. The «temperature» in simulated annealing has the same dimension as the sum of squares - none at all.
+The reference configuration file contains atom positions, which implicitly defines the unit of length. The interaction potential implicitly makes use of a length unit and an energy unit. Of course, this length unit must be the same as for the configuration file. The two units of length, and energy determine other units - like force and pressure - which are derived from them. The //temperature// in simulated annealing has the same dimension as the sum of squares - none at all.
-==  Example  ==
+==== Example ====
-If the length unit is 1 Å = 1e-10 m, and the energy unit is 1 eV = 1.602e-19 J (which corresponds to 11594 K), then the unit of pressure is 160.2 GPa = 1602 kbar, and the unit of force is 1 eV/Å = 1.602e-9 N = 1.602 nN
+If the length unit is $$1~\unicode{x212B} = 1\cdot 10^{-10}~\mathrm{m},$$ and the energy unit is $$1~\mathrm{eV} = 1.602\cdot 10^{-19}~\mathrm{J}$$ (which corresponds to $11594~\mathrm{K}$), then the unit of pressure is $$160.2~\mathrm{GPa} = 1602~\mathrm{kbar},$$ and the unit of force is $$1~\frac{\mathrm{eV}}{\unicode{x212B}} = 1.602\cdot 10^{-9}~\mathrm{N}.$$