1 // ****************************************************************************** 2 // 3 // Title: Force Field X. 4 // Description: Force Field X - Software for Molecular Biophysics. 5 // Copyright: Copyright (c) Michael J. Schnieders 2001-2024. 6 // 7 // This file is part of Force Field X. 8 // 9 // Force Field X is free software; you can redistribute it and/or modify it 10 // under the terms of the GNU General Public License version 3 as published by 11 // the Free Software Foundation. 12 // 13 // Force Field X is distributed in the hope that it will be useful, but WITHOUT 14 // ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 15 // FOR A PARTICULAR PURPOSE. See the GNU General Public License for more 16 // details. 17 // 18 // You should have received a copy of the GNU General Public License along with 19 // Force Field X; if not, write to the Free Software Foundation, Inc., 59 Temple 20 // Place, Suite 330, Boston, MA 02111-1307 USA 21 // 22 // Linking this library statically or dynamically with other modules is making a 23 // combined work based on this library. Thus, the terms and conditions of the 24 // GNU General Public License cover the whole combination. 25 // 26 // As a special exception, the copyright holders of this library give you 27 // permission to link this library with independent modules to produce an 28 // executable, regardless of the license terms of these independent modules, and 29 // to copy and distribute the resulting executable under terms of your choice, 30 // provided that you also meet, for each linked independent module, the terms 31 // and conditions of the license of that module. An independent module is a 32 // module which is not derived from or based on this library. If you modify this 33 // library, you may extend this exception to your version of the library, but 34 // you are not obligated to do so. If you do not wish to do so, delete this 35 // exception statement from your version. 36 // 37 // ****************************************************************************** 38 package ffx.utilities; 39 40 import static org.apache.commons.math3.util.FastMath.PI; 41 42 /** 43 * Library class containing constants such as Avogadro's number. 44 * <p> 45 * SI units: kg, m, s, C, K, mol, lm 46 * <p> 47 * Our typical units: g/mol, Angstrom, psec, elementary charges (+1 proton charge), K, mol, N/A 48 * 49 * @author Jacob M. Litman 50 * @author Michael J. Schnieders 51 * @since 1.0 52 */ 53 public class Constants { 54 55 // The first seven constants the defining constants of SI as of May 20, 2019 (BIPM). 56 57 /** 58 * Hyperfine transition frequency of cesium in Hertz, defining the second. 59 * <p> 60 * <code>DEL_V_Cs_SI = 9192631770L</code> 61 */ 62 public static final long DEL_V_Cs_SI = 9192631770L; 63 64 /** 65 * Speed of light in m/s, defining the meter. 66 * <p> 67 * <code>SPEED_OF_LIGHT_SI = 299792458</code> 68 */ 69 public static final int SPEED_OF_LIGHT_SI = 299792458; 70 71 /** 72 * Planck constant in J*s, defining the kilogram (by defining the derived Joule). 73 * <p> 74 * <code>PLANCK_CONSTANT_SI = 6.62607015E-34d</code> 75 */ 76 public static final double PLANCK_CONSTANT_SI = 6.62607015E-34d; 77 78 /** 79 * Elementary charge in Coulombs, defining the Coulomb. 80 * <p> 81 * <code>ELEMENTARY_CHARGE_SI = 1.602176634E-19d</code> 82 */ 83 public static final double ELEMENTARY_CHARGE_SI = 1.602176634E-19d; 84 85 /** 86 * Boltzmann's constant in J/K, defining the Kelvin. 87 * <p> 88 * <code>BOLTZMANN_SI = 1.380649E-23d</code> 89 */ 90 public static final double BOLTZMANN_SI = 1.380649E-23d; 91 92 /** 93 * Avogadro's number, defining the mol. 94 * <p> 95 * <code>AVOGADRO = 6.02214076E23d</code> 96 */ 97 public static final double AVOGADRO = 6.02214076E23d; 98 99 /** 100 * Luminous efficacy in lm/W, defining the lumen. 101 * <p> 102 * <code>K_CD_SI = 683</code> 103 */ 104 public static final int K_CD_SI = 683; 105 106 /** Constant <code>LITERS_PER_CUBIC_ANGSTROM=1E-30</code> */ 107 public static final double LITERS_PER_CUBIC_ANGSTROM = 1E-30; 108 /** Constant <code>ATM_TO_BAR=1.01325</code> */ 109 public static final double ATM_TO_BAR = 1.01325; 110 /** Constant <code>KCAL_TO_KJ=4.184</code> */ 111 public static final double KCAL_TO_KJ = 4.184; 112 /** Constant <code>KJ_TO_KCAL=1.0 / KCAL_TO_KJ</code> */ 113 public static final double KJ_TO_KCAL = 1.0 / KCAL_TO_KJ; 114 /** Constant <code>METERS_TO_ANG=1E10</code> */ 115 public static final double METERS_TO_ANG = 1E10; 116 /** Constant <code>SEC_TO_PSEC=1E12</code> */ 117 public static final double SEC_TO_PSEC = 1E12; 118 /** Constant <code>KG_TO_GRAMS=1000</code> */ 119 public static final double KG_TO_GRAMS = 1000; 120 /** Constant <code>PSEC_TO_FSEC=1000</code> */ 121 public static final double PSEC_TO_FSEC = 1000; 122 /** Constant <code>FSEC_TO_PSEC=0.001</code> */ 123 public static final double FSEC_TO_PSEC = 0.001; 124 /** 125 * Ideal gas constant in kcal/(mol*K) <code>R = BOLTZMANN_SI * AVOGADRO * 0.001 * KJ_TO_KCAL 126 * </code> 127 */ 128 public static final double R = BOLTZMANN_SI * AVOGADRO * 0.001 * KJ_TO_KCAL; 129 /** 130 * Boltzmann/ideal gas constant in units of g*Ang^2/(mol*psec^2*K). <code> kB = BOLTZMANN_SI * 131 * KG_TO_GRAMS * METERS_TO_ANG * METERS_TO_ANG * AVOGADRO / (SEC_TO_PSEC * SEC_TO_PSEC)</code> 132 */ 133 public static final double kB = 134 BOLTZMANN_SI * KG_TO_GRAMS * METERS_TO_ANG * METERS_TO_ANG * AVOGADRO / (SEC_TO_PSEC 135 * SEC_TO_PSEC); 136 /** Conversion from kcal/mol/Ang^3 to Atm. <code>PRESCON=6.85684112e4</code> */ 137 public static final double PRESCON = 6.85684112e4; 138 /** Permittivity of water at STP. <code>dWater=78.3</code> */ 139 public static final double dWater = 78.3; 140 /** Convert nanoseconds to seconds. <code>NS2SEC=1e-9</code> */ 141 public static final double NS2SEC = 1e-9; 142 /** Room temperature ~= 298.15 Kelvins. <code>ROOM_TEMPERATURE=298.15</code> */ 143 public static final double ROOM_TEMPERATURE = 298.15; 144 /** 145 * Coulomb constant in units of kcal*Ang/(mol*electron^2), as derived from CODATA 2018 permittivity 146 * of free space measured at 8.8541878128*10^-12 F/m <code> 147 * ELECTRIC_CODATA_2018=332.063713299</code> 148 */ 149 public static final double ELECTRIC_CODATA_2018 = 332.063713299; 150 /** 151 * Coulomb constant in units of kcal*Ang/(mol*electron^2) 152 * 153 * <p>Note -- this value varies slightly between force field definitions and can be set using the 154 * ELECTRIC property. As such, it's not updated to SI/CODATA standards, but rather kept up-to-date 155 * with the coulomb parameter in Tinker/source/units.f. At present, the Tinker value is a truncated 156 * version of the Coulomb constant derived from CODATA 2018.<code> 157 * DEFAULT_ELECTRIC=332.063713</code> 158 */ 159 public static final double DEFAULT_ELECTRIC = 332.063713; 160 /** Conversion from electron-Angstroms to Debye. <code>ELEC_ANG_TO_DEBYE=4.80321</code> */ 161 public static final double ELEC_ANG_TO_DEBYE = 4.80321; 162 /** 163 * Conversion from electron-Angstroms^2 to Buckinghams. <code> ELEC_ANG2_TO_BUCKINGHAMS = 164 * ELEC_ANG_TO_DEBYE * ELEC_ANG_TO_DEBYE</code> 165 */ 166 public static final double ELEC_ANG2_TO_BUCKINGHAMS = ELEC_ANG_TO_DEBYE * ELEC_ANG_TO_DEBYE; 167 /** 168 * Conversion from kcal/mole to g*Ang**2/ps**2. <code>KCAL_TO_GRAM_ANG2_PER_PS2=4.1840e2</code> 169 */ 170 public static final double KCAL_TO_GRAM_ANG2_PER_PS2 = 4.1840e2; 171 /** Conversion from Bohr to Angstroms. <code>BOHR=0.52917720859</code> */ 172 public static final double BOHR = 0.52917720859; 173 /** Conversion from Bohr^2 to Angstroms^2. <code>BOHR2 = BOHR * BOHR</code> */ 174 public static final double BOHR2 = BOHR * BOHR; 175 /** 176 * Convert Hartree to kcal/mol. 177 */ 178 public static final double HARTREE_TO_KCAL_PER_MOL = 627.5094738898777; 179 /** 180 * Degrees per radian. 181 */ 182 public static final double DEGREES_PER_RADIAN = 180.0 / PI; 183 184 // Library class: make the default constructor private to ensure it's never constructed. 185 private Constants() { 186 } 187 }