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  2. Quantum chemistry composite methods - Wikipedia

    en.wikipedia.org/wiki/Quantum_chemistry...

    The T1 procedure reproduces these values with mean absolute and RMS errors of 1.8 and 2.5 kJ/mol, respectively. T1 reproduces experimental heats of formation for a set of 1805 diverse organic molecules from the NIST thermochemical database [ 14 ] with mean absolute and RMS errors of 8.5 and 11.5 kJ/mol, respectively.

  3. Multi-configurational self-consistent field - Wikipedia

    en.wikipedia.org/wiki/Multi-configurational_self...

    This Hartree–Fock model gives a reasonable description of H 2 around the equilibrium geometry – about 0.735 Å for the bond length (compared to a 0.746 Å experimental value) and 350 kJ/mol (84 kcal/mol) for the bond energy (experimentally, 432 kJ/mol (103 kcal/mol) [1]). This is typical for the HF model, which usually describes closed ...

  4. Hartree - Wikipedia

    en.wikipedia.org/wiki/Hartree

    The hartree (symbol: E h), also known as the Hartree energy, is the unit of energy in the atomic units system, named after the British physicist Douglas Hartree. Its CODATA recommended value is E h = 4.359 744 722 2060 (48) × 10 −18 J ‍ [ 1 ] = 27.211 386 245 981 (30) eV .

  5. Heats of vaporization of the elements (data page) - Wikipedia

    en.wikipedia.org/wiki/Heats_of_vaporization_of...

    kJ/mol 1 H hydrogen (H 2) use (H 2) 0.904 CRC (H 2) 0.90 LNG: ... Values refer to the enthalpy change in the conversion of liquid to gas at the boiling point (normal ...

  6. Hartree equation - Wikipedia

    en.wikipedia.org/wiki/Hartree_equation

    In order to solve the equation of an electron in a spherical potential, Hartree first introduced atomic units to eliminate physical constants. Then he converted the Laplacian from Cartesian to spherical coordinates to show that the solution was a product of a radial function () / and a spherical harmonic with an angular quantum number , namely = (/) (,).

  7. Standard enthalpy of formation - Wikipedia

    en.wikipedia.org/wiki/Standard_enthalpy_of_formation

    The standard enthalpy of formation is measured in units of energy per amount of substance, usually stated in kilojoule per mole (kJ mol −1), but also in kilocalorie per mole, joule per mole or kilocalorie per gram (any combination of these units conforming to the energy per mass or amount guideline).

  8. Hybrid functional - Wikipedia

    en.wikipedia.org/wiki/Hybrid_functional

    The hybrid approach to constructing density functional approximations was introduced by Axel Becke in 1993. [1] Hybridization with Hartree–Fock (HF) exchange (also called exact exchange) provides a simple scheme for improving the calculation of many molecular properties, such as atomization energies, bond lengths and vibration frequencies, which tend to be poorly described with simple "ab ...

  9. Water (data page) - Wikipedia

    en.wikipedia.org/wiki/Water_(data_page)

    6.01 kJ/mol Entropy change of fusion at 273.15 K, 1 bar, Δ fus S: 22.0 J/(mol·K) Std enthalpy change of vaporization, Δ vap H o: 44.0 kJ/mol Enthalpy change of vaporization at 373.15 K, Δ vap H: 40.68 kJ/mol Std entropy change of vaporization, Δ vap S o: 118.89 J/(mol·K) Entropy change of vaporization at 373.15 K, Δ vap S: 109.02 J/(mol ...