Q-HOP MD simulation


Just Got Here
Hello,

I spent some days figuring out how to perform quantum hop molecular dynamics simulations but I'm getting some strange errors in when running the prepare module. I have read the NWChem documentation (specially that about the prepare and MD modules) and some articles (AKBARI, Saeed, et al. ChemPhysChem, 2017, vol. 18, no 23, p. 3485-3497, Devanathan, Ram, et al. The Journal of Physical Chemistry B 114.43 (2010): 13681-13690...) that have performed these simulations but I could't find any example or specific working input files.

I'm trying to take the example of benzene [1] from the NWChem repository and modify it to run a single benzene molecule solvated in water allowing proton hopping. Here is the content of my "benzene.nw" file based on that of the example and modifying it according to the documentation:

start benzene

prepare
 system benzene_em
 new_top new_seq
 solvate
 modify segment 1 protonation 1
 update lists
 ignore
 qhop
end

task prepare


When run this input file I get the following output:

 argument  1 = benzene.nw




              Northwest Computational Chemistry Package (NWChem) 6.6
              ------------------------------------------------------


                    Environmental Molecular Sciences Laboratory
                       Pacific Northwest National Laboratory
                                Richland, WA 99352

                              Copyright (c) 1994-2015
                       Pacific Northwest National Laboratory
                            Battelle Memorial Institute

             NWChem is an open-source computational chemistry package
                        distributed under the terms of the
                      Educational Community License (ECL) 2.0
             A copy of the license is included with this distribution
                              in the LICENSE.TXT file

                                  ACKNOWLEDGMENT
                                  --------------

            This software and its documentation were developed at the
            EMSL at Pacific Northwest National Laboratory, a multiprogram
            national laboratory, operated for the U.S. Department of Energy
            by Battelle under Contract Number DE-AC05-76RL01830. Support
            for this work was provided by the Department of Energy Office
            of Biological and Environmental Research, Office of Basic
            Energy Sciences, and the Office of Advanced Scientific Computing.


           Job information
           ---------------

    hostname        = sun014
    program         = /opt/nwchem-6.6/bin/LINUX64/nwchem
    date            = Mon Mar 11 12:37:50 2019

    compiled        = Thu_Mar_07_12:05:29_2019
    source          = /opt/nwchem-6.6
    nwchem branch   = 6.6
    nwchem revision = 27746
    ga revision     = 10594
    input           = benzene.nw
    prefix          = benzene.
    data base       = ./benzene.db
    status          = startup
    nproc           =        1
    time left       =     -1s



           Memory information
           ------------------

    heap     =   13107196 doubles =    100.0 Mbytes
    stack    =   13107201 doubles =    100.0 Mbytes
    global   =   26214400 doubles =    200.0 Mbytes (distinct from heap & stack)
    total    =   52428797 doubles =    400.0 Mbytes
    verify   = yes
    hardfail = no


           Directory information
           ---------------------

  0 permanent = .
  0 scratch   = .




                                NWChem Input Module
                                -------------------


                                  Prepare Module
                                  --------------

 Force field                           amber


 Directories used for fragment and segment files

                                       /opt/nwchem-6.6/src/data/amber_s/
                                       /opt/nwchem-6.6/src/data/amber_q/
                                       /opt/nwchem-6.6/src/data/amber_x/
                                       /opt/nwchem-6.6/src/data/amber_u/
                                       ./

 Parameter files used to resolve force field parameters

                                       /opt/nwchem-6.6/src/data/amber_s/amber.par
                                       /opt/nwchem-6.6/src/data/amber_q/amber.par
                                       /opt/nwchem-6.6/src/data/amber_x/amber.par
                                       /opt/nwchem-6.6/src/data/amber_u/amber.par
                                       ./amber.par

 Deleted existing topology             benzene.top

 Deleted existing sequence             ./benzene.seq

 PDB geometry                          benzene.pdb


 Created sequence                      ./benzene.seq


 Parameter file                        /opt/nwchem-6.6/src/data/amber_s/amber.par
 Parameter file                        /opt/nwchem-6.6/src/data/amber_q/amber.par
 Parameter file                        /opt/nwchem-6.6/src/data/amber_x/amber.par
 Parameter file                        /opt/nwchem-6.6/src/data/amber_u/amber.par

 Total charge                              0.000000
 qhop_setup

Program received signal SIGSEGV: Segmentation fault - invalid memory reference.

Backtrace for this error:
#0  0x7f1e51eab89d in ???
#1  0x7f1e51eaaae3 in ???
#2  0x7f1e51752fbf in ???
#3  0x56345fcbf5e2 in ???
#4  0x56345fcc341a in ???
#5  0x56345f5b3530 in ???
#6  0x56345f571d72 in ???
#7  0x56345f54c42f in ???
#8  0x56345ec5cf11 in task_
        at /opt/nwchem-6.6/src/task/task.F:340
#9  0x56345ec54f18 in nwchem
        at /opt/nwchem-6.6/src/nwchem.F:285
#10  0x56345ec5555f in main
        at /opt/nwchem-6.6/src/nwchem.F:369

-------------------------------------------------------
Primary job  terminated normally, but 1 process returned
a non-zero exit code. Per user-direction, the job has been aborted.
-------------------------------------------------------


If I remove the qhop in the input file there is no error in the output so my guess is that I am missing some kind of input information or something else. I am pretty sure that my NWChem installation is correct (I can run all the examples: dft, md, optimization...).

I was wondering to know if someone could provide a simple working example, e.g. q-hop in pure water or maybe with a simple molecule solvated, or let me know if there is some trick that I'm missing.

Thank you very much in advance.


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