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nuclear-electronic_orbital_method [2023/08/21 09:36] – [NEO examples] rmatalhasecknuclear-electronic_orbital_method [2024/10/25 16:09] (current) – remove link to basis.php may
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-====== Nuclear-electron orbital (NEO) method ======+====== Nuclear-electronic orbital (NEO) method ======
  
-The [[https://doi.org/10.1021/acs.chemrev.9b00798|Nuclear-electron orbital (NEO)]] method pioneered by Hammes-Schiffer and coworkers is available in **''Molpro''** for density fitted spin-restricted NEO-Hartree-Fock as well as a local-density fitting variant. It allows to handle a selected number of hydrogen nuclei as quantum particles by building a second Fock-matrix for the latter, coupling both subsystems (electrons and quantum protons) by a Coulomb operator. Further information about the method can be found in a  [[https://doi.org/10.21203/rs.3.rs-3231458/v1|preprint]].+The [[https://doi.org/10.1021/acs.chemrev.9b00798|Nuclear-electron orbital (NEO)]] method pioneered by Hammes-Schiffer and coworkers is available in **''Molpro''** for density fitted spin-restricted NEO-Hartree-Fock as well as a local-density fitting variant. It allows to handle a selected number of hydrogen nuclei as quantum particles by building a second Fock-matrix for the latter, coupling both subsystems (electrons and quantum protons) by a Coulomb operator. Further information about the method can be found [[https://doi.org/10.1021%2Facs.jctc.3c01055|here]].
  
   * **''DF-NEO-RHF'', //options//** calls the density-fitted NEO-Hartree-Fock program   * **''DF-NEO-RHF'', //options//** calls the density-fitted NEO-Hartree-Fock program
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 </code> </code>
  
-The electronic basis set can be freely chosen from the [[https://www.molpro.net/info/basis.php|Molpro basis set library]]. At the current stage no user defined mixed basis sets are possible within the NEO programs. +The electronic basis set can be freely chosen from the Molpro basis set library. At the current stage no user defined mixed basis sets are possible within the NEO programs. 
  
 The nuclear basis set is defined via the **''nucbas''** keyword. The default basis for nuclear basis sets must be defined in every case as the **''neo-basis''**. Afterwards, the selected NEO centers can be assigned with the desired basis set. It is highly recommended to use the specifically tailored [[https://doi.org/10.1063/5.0009233|PB basis sets]] for multicomponent methods developed by Hammes-Schiffer and coworkers. Note that all NEO centers need to be assigned individually with the same basis set. The nuclear basis set is defined via the **''nucbas''** keyword. The default basis for nuclear basis sets must be defined in every case as the **''neo-basis''**. Afterwards, the selected NEO centers can be assigned with the desired basis set. It is highly recommended to use the specifically tailored [[https://doi.org/10.1063/5.0009233|PB basis sets]] for multicomponent methods developed by Hammes-Schiffer and coworkers. Note that all NEO centers need to be assigned individually with the same basis set.
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   * **''NEORD'', //number//** sets the start for the fast rotational update of the orbitals in the local version   * **''NEORD'', //number//** sets the start for the fast rotational update of the orbitals in the local version
   * **''NOBLOCKDIAG''** disables the block diagonalization of the nuclear starting guess (this is generally not recommended!!)   * **''NOBLOCKDIAG''** disables the block diagonalization of the nuclear starting guess (this is generally not recommended!!)
 +  * **''NEOMIXBAS''** enables the use of user-defined mixed basis sets (see example for use)
 +===== Adaptive NEO =====
  
 +Optimization of quantum nuclei positions with the adaptive NEO approach, where the nuclear centroids are computed on-the-fly during the SCF iterations. This procedure is available by using the 
 +
 +<code>
 +ADAPTIVE
 +</code>
 +keyword in the NEO program input card.
 +
 +==== Threshold ====
 +
 +The thresholds for the convergence criteria of the nuclear centers during an adaptive NEO computation can be adjusted with the following keyword
 +
 +  * **''ADTHRES'', //number//** sets the convergence threshold for the nuclear centers in atomic units
 +  * **''ADITER'', //number//** sets the initial iteration for the start of the adaptive procedure (default=2)
 +==== Damping ====
 +
 +The shift of the nuclear basis function center towards the charge centroid can be damped with the following keyword
 +
 +  * **''ADDUMP'', //number//** sets the damping factor of the nuclear centroid shift
  
 ===== NEO examples ===== ===== NEO examples =====
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 </code> </code>
  
-The second example shows the input of a **''LDF-NEO-RHF''** computation of the same molecule starting from a prior RHF calculation. +The second example shows the input of a **''LDF-NEO-RHF''** computation of the same molecule starting from a prior RHF calculation. In this example a [[dump_density_or_orbital_values_cube|cube]] file is requested. This will output the quantum nuclei density.
  
 <code> <code>
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 {ldf-neo-rhf,maxdis=10,maxit=200,df_basis=cc-pvdz} {ldf-neo-rhf,maxdis=10,maxit=200,df_basis=cc-pvdz}
  
-{cube,nuclear_density.cube;density,2102.2}+{cube,nuclear.cube;density,2102.2}
 </code> </code>
  
 +The following example shows a NEO calculation, where a user-defined mixed basis set is used. Thereby, the electronic basis set at the quantum nuclei is larger than for regular hydrogen atoms. The use of the **''NEOMIXBAS''** requires the additional definition of the **''elebas''** and **''elefit''** basis sets as shown below.
 +
 +<code>
 +memory,50,m
 +gdirect
 +nosym
 +
 +geometry={
 +3
 +
 +H1  -3.5008791    1.2736107    0.7596000
 +H2  -4.9109791    1.2967107    0.1521000
 +O   -3.9840791    1.3301107   -0.0574000
 +}
 +
 +charge=0
 +
 +basis={
 +default=cc-pvtz
 +H1=cc-pv5z
 +
 +set,nucbas
 +default=neo-basis
 +H1=pb4-f2
 +
 +set,nucfit
 +default=neo-basis
 +H1=10s10p10d10f
 +
 +set,elebas
 +default=cc-pvtz
 +H1=cc-pv5z
 +
 +set,elefit,context=jkfit
 +default=cc-pvtz
 +H1=cc-pv5z
 +}
 +
 +qnuc,H1
 +
 +{df-neo-rhf,maxdis=10,maxit=1000,df_basis=elefit
 +neoatden
 +neomixbas
 +}
 +</code>
 +
 +The example below shows the input for an adaptive NEO calculation, where the nuclear basis function centers convergence is set below 1E-5 bohr and a damping factor of 0.5 is applied.
 +
 +<code>
 +memory,50,m
 +gdirect
 +nosym
 +
 +geometry={
 +3
 +
 +H1  -3.5008791    1.2736107    0.7596000
 +H2  -4.9109791    1.2967107    0.1521000
 +O   -3.9840791    1.3301107   -0.0574000
 +}
 +
 +charge=0
 +
 +basis={
 +default=cc-pvdz
 +
 +set,nucbas
 +default=neo-basis
 +H1=pb4-f2
 +
 +set,nucfit
 +default=neo-basis
 +H1=10s10p10d10f
 +}
 +
 +qnuc,H1
 +
 +{df-neo-rhf,maxdis=10,maxit=500,df_basis=cc-pvdz
 +adaptive
 +adthres,1.d-5
 +addump,0.5
 +}
 +</code>
 ===== Bibliography ===== ===== Bibliography =====
  
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 ===(L)DF-NEO-RHF=== ===(L)DF-NEO-RHF===
  
-Lukas Hasecke, and Ricardo A. Mata [[https://doi.org/10.21203/rs.3.rs-3231458/v1|Nuclear quantum effects made accessible: local-density fitting in multicomponent methods]] //Research Square// **2023** preprint. +Lukas Hasecke, and Ricardo A. Mata [[https://doi.org/10.1021/acs.jctc.3c01055|Nuclear Quantum Effects Made Accessible: Local Density Fitting in Multicomponent Methods]] //J. Chem. Theory Comput.// **2023** //19// (22), 8223–8233.