Questions tagged [cp2k]

For questions about (or related to) the software CP2K.

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7
votes
0answers
75 views

Setup for 4-point flexible water model

I tried to search online if there are examples or suggestions on how to setup a 4-point flexible water model, such as TIP4P/2005f, qTIP4P/f, TIP4P/$\epsilon$ FLEX, etc. but there's no clear example on ...
6
votes
0answers
43 views

Molecular dynamics to reproduce dispersion interactions

I'm trying to simulate the behavior of chromophore molecules incorporated into a polymer under an external electric field. I've tried to use classical molecular dynamics (GROMACS) but it's unable to ...
6
votes
0answers
76 views

What is a "charged system" in this specific context?

I'm doing a polarization calculation for the first time. To specify one of the input parameters (the "reference point") correctly, I have to figure out if my system is "charged." ...
5
votes
0answers
40 views

Kinetic energy cut-off for Gaussian-type orbitals when applying periodic boundary conditions [duplicate]

I have a solid with PBC (periodic boundary conditions) and I want to perform a DFT simulation. I use GTO as the basis. In a paper I read, I can transform the GTO to a Bloch function (crystalline ...
10
votes
1answer
54 views

Reading complex potential into CP2K

Is it possible to read a complex potential into CP2K? I have generated a potential using FDTD at a given frequency, which results in a complex result. The potential is to be read in to a real time ...
7
votes
0answers
50 views

CP2K Spherical Cell [closed]

I'm trying to run a gas phase cluster calculation in CP2K. I want to create an outside force to constrain water molecules that are in the simulation within a radius of a central ion. I want to create ...
7
votes
1answer
144 views

cp2k conserved quantity changed when restart NVT MD?

The details are descripted elsewhere, but got no answer for days, so I post it here for help. As title said, I noticed a relatively big change in conserved quantity and don't know why. I've upload ...
14
votes
1answer
97 views

Is basis set superposition error reduced when using the GAPW method?

CP2K implements the Gaussian and Augmented Planewaves (GAPW) approach for all-electron calculations. My understanding is that the GAPW method involves using atom-centered Gaussian type orbitals to ...
10
votes
0answers
85 views

Periodic polarizable QM/MM embedding

Are there any standalone open source software codes available for periodic polarizable QM/MM embedding MD simulations? In my knowledge, CP2K only has the option for electrostatic embedding and other ...
8
votes
1answer
113 views

Failure of CP2K density functional software to converge for a 64 Si atom amorphous structure

The structure was created using Stillinger Weber with LAMMPS. The command I used was the following: ...
13
votes
0answers
147 views

CP2K vs BigDFT comparison

I typically run DFT calculations with 1000 to 5000 atoms using CP2K. This works fine but I'm interested in BigDFT also. Is there anyone here that has experience using BigDFT and is able to compare ...
12
votes
1answer
187 views

Geometric optimization taking a long time. Are my convergence criteria too tight in CP2K?

I have been having trouble with the VIBRATIONAL_ANALYSIS routine. Namely, the routine keeps timing out. I am trying to find the vibrational modes of Pyridine in a non periodic system, as well as $\ce{...
8
votes
1answer
127 views

Reading in E-field with CP2K

I have figured out a way to input a custom electric field in a .cube format, but I am not sure I am doing it in the proper way. Currently my file contains information for the magnitude of the electric ...
7
votes
1answer
74 views

What are the default units for the core hamiltonian and the density AO matrices in CP2K?

I have a few questions about default units. I am trying to find the default units for the density matrix and the core hamiltonian. I am assuming they are in e/(bohr)$^3$ and Hartrees respectively. I ...
16
votes
1answer
193 views

Is there any reason not to sum the kinetic and potential energy from an NPT simulation to get internal energy?

I would be very grateful for some newbie-level advice from a thermodynamics guru. I ran NPT simulations on a particular system (in CP2K software) to get fluid densities for use in fluid dynamics ...
10
votes
2answers
188 views

What are some methods for modeling bulk phase infrared spectra?

I am interested in predicting the infrared spectra of bulk phase molecules, it seems that AIMD (ab initio molecular dynamics) is the current best approach. I have found a tutorial on using CP2K to do ...
8
votes
1answer
213 views

Is it possible to use the Parrinello-Rahman barostat for NPT simulations in CP2K?

It is possible to use different types of thermostats in CP2K by specifying them in the corresponding section of the input as mentioned here. But there is no mention of specifying the barostat type in ...
15
votes
2answers
814 views

What exactly is the "Optimizer" in CP2K geometry optimization?

I'm just now starting to use the program CP2K, and I am having trouble understanding the difference between the optimizer options (CG, BFGS, LBFGS). I have seen ...