This site has been originally devised as addon material for manuscript M. Kroger, O. Peleg, Y. Ding, Y. Rabin, Soft Matter 4 (2008) 18-28. Reduced units - online interactive tool You have to provide three experimental quantities and their dimensionless counterpart of a computer simulation (using reduced units, so called for convenience) Example: In a computer simulation, you measure bond length = 0.8, temperature = 2, mass of a particle = 1. In the experiment (system of polymer chains, modelled by united atoms, say, but it works for any system) for which the simulation has been designed, the bond length is known as 1.56 Angstrom, at temperature 450 Kelvin, and the mass of united atom is 28 a.u. A trivial task is to write these experimental values in S.I. units. For this particularly difficult example, you have to express Kelvin and a.u. in S.I. units before you can start using this tool. Use the Boltzmann constant kB to change from temperature to energy (with has S.I. unit), and calculate a.u. abbreviating g/mol using g = kg/1000 and mol = 6.023e+23. We arrive at bond length is known as 1.56e-10 kg0m1s0, at thermal energy 6.2129268e-21 kg1m2s-2, and the mass of united atom is 4.64884608998838e-26 kg1m0s0 Now we can enter these values into the table and hereafter press the 'Submit' bottom: name of quantity simulated value experimental value in S.I. units 1.) LJulength = × kg00 -6-5-4-3-2-10123456m10 -6-5-4-3-2-10123456s00 -6-5-4-3-2-10123456 2.) LJuenergy = × kg10 -6-5-4-3-2-10123456m20 -6-5-4-3-2-10123456s-20 -6-5-4-3-2-10123456 3.) LJumass = × kg10 -6-5-4-3-2-10123456m00 -6-5-4-3-2-10123456s00 -6-5-4-3-2-10123456 load sample data: LJu »» | JCu (G3) »» | JCu (G4) »» © mk 2025
Example:
In a computer simulation, you measure
bond length = 0.8, temperature = 2, mass of a particle = 1.
In the experiment (system of polymer chains, modelled by united atoms, say, but it works for any system) for which the simulation has been designed, the
bond length is known as 1.56 Angstrom, at temperature 450 Kelvin, and the mass of united atom is 28 a.u.
A trivial task is to write these experimental values in S.I. units. For this particularly difficult example, you have to express Kelvin and a.u. in S.I. units before you can start using this tool. Use the Boltzmann constant kB to change from temperature to energy (with has S.I. unit), and calculate a.u. abbreviating g/mol using g = kg/1000 and mol = 6.023e+23. We arrive at
bond length is known as 1.56e-10 kg0m1s0, at thermal energy 6.2129268e-21 kg1m2s-2, and the mass of united atom is 4.64884608998838e-26 kg1m0s0
Now we can enter these values into the table and hereafter press the 'Submit' bottom:
mk
2025