mirror of https://github.com/QMCPACK/qmcpack.git
81 lines
3.6 KiB
TeX
81 lines
3.6 KiB
TeX
\chapter{Examples}
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\label{chap:examples}
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\textbf{WARNING: THESE EXAMPLES ARE NOT CONVERGED! YOU MUST CONVERGE PARAMETERS (SIMULATION CELL SIZE, JASTROW PARAMETER NUMBER/CUTOFF, TWIST NUMBER, DMC TIME STEP, DFT PLANE WAVE CUTOFF, DFT K-POINT MESH, ETC.) FOR REAL CALCUATIONS!}
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The following examples should run in serial on a modern workstation in a few hours.
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\section{Using QMCPACK directly}
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In \texttt{examples/molecules}, there are the following examples.
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Each directory also contains a \texttt{README} file with more details.
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\begin{tabular}{l l}
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Directory & Description \\
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\texttt{H2O} & H2O molecule from GAMESS orbitals \\
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\texttt{He} & Helium atom with simple wavefunctions\\
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\end{tabular}
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\section{Using Nexus}
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For more information about Nexus, see the User Guide in \texttt{nexus/documentation}.
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For Python to find the Nexus library, the PYTHONPATH environment variable should be set to \texttt{<QMCPACK source>/nexus/library}.
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For these examples to work properly, the executables for Quantum ESPRESSO and QMCPACK either
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need to be on the path, or the paths in the script should be adjusted.
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These examples can be found under the \texttt{nexus/examples/qmcpack} directory.
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%\begin{itemize}
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%\item \texttt{diamond} Bulk diamond with VMC
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%\item \texttt{graphene} Graphene sheet with DMC
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%\item \texttt{c20} C20 cage molecule
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%\item \texttt{oxygen\_dimer} Binding curve for O$_2$ molecule
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%\item \texttt{H2O} H$_2$O molecule with Quantum ESPRESSO orbitals
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%\item \texttt{LiH} LiH crystal with Quantum ESPRESSO orbitals
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%\end{itemize}
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\begin{tabular}{l l}
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Directory & Description \\
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\texttt{diamond} & Bulk diamond with VMC \\
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\texttt{graphene} & Graphene sheet with DMC \\
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\texttt{c20} & C20 cage molecule \\
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\texttt{oxygen\_dimer} & Binding curve for O$_2$ molecule \\
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\texttt{H2O} & H$_2$O molecule with Quantum ESPRESSO orbitals \\
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\texttt{LiH} & LiH crystal with Quantum ESPRESSO orbitals \\
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\end{tabular}
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%\subsection{Bulk diamond}
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%The input files are in the directory \texttt{nexus/examples/qmcpack/diamond}.
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%\subsection{Graphene Sheet}
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%The input files are in the directory \texttt{nexus/examples/qmcpack/graphene}.
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%\subsection{C20 cage molecule}
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%The input files are in the directory \texttt{nexus/examples/qmcpack/c20}.
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%\subsection{Binding curve for O$_2$ molecule}
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%The input files are in the directory \texttt{nexus/examples/qmcpack/oxygen\_dimer}.
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%\subsection{H$_2$O molecule with Quantum ESPRESSO orbitals}
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%
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%The input files are in the directory \texttt{nexus/examples/qmcpack/H2O}.
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%The Nexus script is in \texttt{H2O.py} and \texttt{H2O.xyz} contains the atomic positions.
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%To run the example, the BFD pseudopotentials are needed. Create a \texttt{pseudopotentials} directory, and copy \texttt{O.BFD.upf}, \texttt{O.BFD.xml}, \texttt{H.BFD.upf}, and \texttt{H.BFD.xml} from \texttt{pseudopotentials/BFD} in the QMCPACK distribution.
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%
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%The \texttt{H2O.py} script generates the orbitals using Quantum ESPRESSO, runs QMCPACK to optimize the Jastrow and then performs DMC for H$_2$O in a box.
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%
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%
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%
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%\subsection{LiH crystal with Quantum ESPRESSO orbitals}
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%The input files are in the directory \texttt{nexus/examples/qmcpack/LiH}.
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%
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%The \texttt{LiH.py} Nexus script uses CASINO-formatted Trail-Needs pseudopotentials (see Section \ref{subsec:CASINO}) for Li and H in a subdirectory named \texttt{pseudopotentials} (both UPF and CASINO formats, named \texttt{Li.TN-DF.upf}, \texttt{Li.pp.data}, \texttt{H.TN-DF.upf}, and \texttt{H.pp.data}, respectively), generates the orbitals using Quantum ESPRESSO, then runs QMCPACK to optimize the Jastrow and run DMC for LiH with periodic boundary conditions.
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