Handy conversion constants

These are a set of multiplicative factors for use in converting among the various commonly used molecular mechanics units. More...

Variables
static const Real	SimTK::DuMM::Ang2Nm = (Real)0.1L
	angstroms to nanometers
static const Real	SimTK::DuMM::Nm2Ang = (Real)10.L
	nanometers to angstroms
static const Real	SimTK::DuMM::Deg2Rad = (Real)SimTK_DEGREE_TO_RADIAN
	degrees to radians
static const Real	SimTK::DuMM::Rad2Deg = (Real)SimTK_RADIAN_TO_DEGREE
	radians to degrees
static const Real	SimTK::DuMM::KJ2Kcal = (Real)SimTK_KJOULE_TO_KCAL
	kilojoules to kilocalories
static const Real	SimTK::DuMM::Kcal2KJ = (Real)SimTK_KCAL_TO_KJOULE
	kilocalories to kilojoules
static const Real	SimTK::DuMM::Sigma2Radius = (Real)std::pow(2.L, 1.L/6.L)
	half-Sigma to van der Waals radius; caution -- see discussion in module description.
static const Real	SimTK::DuMM::Radius2Sigma = (Real)std::pow(2.L, -1.L/6.L)
	van der Waals radius to half-Sigma; caution -- see discussion in module description.

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Detailed Description

These are a set of multiplicative factors for use in converting among the various commonly used molecular mechanics units.

Note that these are compilation-unit statics, not members. That way we can be sure they are initialized before being used. To use these, multiply something in units on left of the "2" to get equivalent in units on right. E.g., 180*Deg2Rad gives Pi radians.

There are several conventions for giving van der Waals parameters. Rmin is the radius at which the energy well minimum is seen (actually it is 1/2 the distance between atom centers for a pair of atoms of this class interacting with that minimum energy). This is not the Lennard-Jones term (half-) Sigma, which is the radius (half distance between atom centers) at which the energy crosses zero, that is, a little closer together than when the energy well is at maximum depth. To convert for Lennard-Jones: Rmin = 2^(1/6) * Sigma. NOTE: in many cases the Lennard-Jones data will be "diameter" Sigma, that is, twice the value our conversion constant is expecting -- be careful!

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Variable Documentation

const Real SimTK::DuMM::Ang2Nm = (Real)0.1L [static]

angstroms to nanometers

const Real SimTK::DuMM::Nm2Ang = (Real)10.L [static]

nanometers to angstroms

const Real SimTK::DuMM::Deg2Rad = (Real)SimTK_DEGREE_TO_RADIAN [static]

degrees to radians

const Real SimTK::DuMM::Rad2Deg = (Real)SimTK_RADIAN_TO_DEGREE [static]

radians to degrees

const Real SimTK::DuMM::KJ2Kcal = (Real)SimTK_KJOULE_TO_KCAL [static]

kilojoules to kilocalories

const Real SimTK::DuMM::Kcal2KJ = (Real)SimTK_KCAL_TO_KJOULE [static]

kilocalories to kilojoules

const Real SimTK::DuMM::Sigma2Radius = (Real)std::pow(2.L, 1.L/6.L) [static]

half-Sigma to van der Waals radius; caution -- see discussion in module description.

const Real SimTK::DuMM::Radius2Sigma = (Real)std::pow(2.L, -1.L/6.L) [static]

van der Waals radius to half-Sigma; caution -- see discussion in module description.