| /// \file |
| /// Contains constants for unit conversions. |
| /// |
| /// The units for this code are: |
| /// - Time in femtoseconds (fs) |
| /// - Length in Angstroms (Angs) |
| /// - Energy in electron Volts (eV) |
| /// - Mass read in as Atomic Mass Units (amu) and then converted for |
| /// consistency (energy*time^2/length^2) |
| /// Values are taken from NIST, http://physics.nist.gov/cuu/Constants/ |
| |
| #ifndef _CONSTANTS_H_ |
| #define _CONSTANTS_H_ |
| |
| /// 1 amu in kilograms |
| #define amuInKilograms 1.660538921e-27 |
| |
| /// 1 fs in seconds |
| #define fsInSeconds 1.0e-15 |
| |
| /// 1 Ang in meters |
| #define AngsInMeters 1.0e-10 |
| |
| /// 1 eV in Joules |
| #define eVInJoules 1.602176565e-19 |
| |
| /// Internal mass units are eV * fs^2 / Ang^2 |
| static const double amuToInternalMass = |
| amuInKilograms * AngsInMeters * AngsInMeters |
| / (fsInSeconds * fsInSeconds * eVInJoules); |
| |
| /// Boltmann constant in eV's |
| static const double kB_eV = 8.6173324e-5; // eV/K |
| |
| /// Hartrees to eVs |
| static const double hartreeToEv = 27.21138505; |
| |
| /// Bohrs to Angstroms |
| static const double bohrToAngs = 0.52917721092; |
| |
| #endif |
