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Questions tagged [software]

For questions about matter modeling software. Questions can be about usage or recommendations.

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4
votes
2answers
309 views

Soil Modelling: Getting accurate Thermal Conductivity values

Context: We perform a lot of CFD (Computational Fluid Dynamics) modelling for our clients (geothermal, construction, general underground engineering, etc) where we have to model temperature flows and ...
5
votes
0answers
53 views

DMRG packages with an easy learning curve for studying the quantum spin systems at zero as well as finite T

What are the DMRG packages with an easy learning curve for studying the quantum spin systems for following purpose: Finding the magnetization curves (M vs H) for 1D spin Hamiltonians [Heisenberg ...
4
votes
0answers
33 views

Simulate drain current gate voltage for QDFET

I've modeled a QDFET transistor of sorts at an atomic scale, as it's not a standard MOSFET, and was wondering how to do a drain current/gate voltage simulation. I don't really have any idea how to ...
5
votes
0answers
48 views

How can I add double bonds to Triazine-derivatives for OpenBabel generation of pdbqt files?

The double bonds are initially present at the sdf file but disappear or are misplaced after .pdbqt conversion. I tried all kinds of combinations using renumbering ...
12
votes
1answer
224 views

Comparing GAMESS, OpenMOLCAS and Psi4

Over the years many open-source ab initio packages have been developed and the diversity in subroutines, methods and portability (ability to interface with other software) is quite varied for ...
5
votes
1answer
86 views

How to run multiples VASP files named as POSCAR-XYZ

Is it possible to direct VASP to read a POSCAR-xyz file instead of reading the default POSCAR? For example, I want to run VASP in the Quantum ESPRESSO format: ...
5
votes
0answers
66 views

How to extract Cartesian gradient with more digits than 8 using Gaussian?

I would like to obtain the Cartesian gradient from a Gaussian formatted checkpoint file with more digits than 8 (specified in scientific notation). Is there any way to do this?
3
votes
0answers
28 views

Convert PSP8 pseudopotential files to UPF format

Is there a way to convert psp8 pseudopotential files (used for abinit) to UPF format (used for Quantum ESPRESSO)? I noticed there is the upfconv.x utility in ...
7
votes
0answers
47 views

How can I calculate the exchange energy for a molecule in PySCF?

I am trying to generate exchange energy separately in pyscf but didn't see a way to do that. For correlation energy, it's fairly simple but do you have any idea how to calculate exchange energy?
4
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0answers
36 views

Calculating emission spectrum of organic compounds by DFT. Can someone elaborate in terms of calculating it for aggregatrion induced emission? [closed]

I am planning for the calculation of emission spectra of organic compounds showing the phenomenon of aggregation-induced emission (AIE). Can someone help me get started?
8
votes
3answers
147 views

How do you generate 3D electron density from fchk file without the Gaussian software?

I'm trying to reproduce some results from a paper with fchk output files containing DFT calculations. The paper details how to produce the 3D electron density using Gaussian software, but since I don'...
16
votes
2answers
408 views

How should I organize and keep track of a huge number of calculations systematically?

Doing matter modeling generates vast amounts of data. We might most probably be working on different projects simultaneously. We definitely will have to revisit old data for revisions, post-processing,...
11
votes
1answer
224 views

What units are used in Gaussian 16 for dipole derivatives output?

I ran a frequency analysis employing Gaussian 16 on MP2/6-31+G(d,p) level of theory with the keyword iop(7/33=1) in order to have access to dipole derivatives with ...
13
votes
1answer
303 views

GUI for DFT calculations

I am a beginner in DFT. Can someone suggest a good DFT software with a GUI for simulating dipole moments and optical absorption spectra in an organic crystal? I have tried the Burai GUI of Quantum ...
8
votes
1answer
73 views

Excited states using ORMAS flag in GAMESS

I am trying to calculate the excited states using single reference CISD on $\ce{CH3OH},$ using ORMAS' CI-X option in GAMESS. As a test example I am using the $\ce{CH3OH}$ that has 2 core, 7 occ. ...
12
votes
1answer
150 views

Functional group detection from geometry

I am currently looking for an efficient way to detect common functional groups - that is, characterize whether a molecule is an alcohol, an aromatic compound, etc. - in a larger database consisting of ...
7
votes
2answers
187 views

Converting SDF to PDBQT using OpenBabel

I want to convert several molecules from sdf format to pdbqt using OpenBabel. However, I can't find ...
4
votes
1answer
83 views

Excited determinants, electronic partition function and thermochemistry calculation

While studying statistical thermodynamics I came across the partition functions, which connect the quantum world to the macroscopic world. I understand that partition functions are used to calculate ...
9
votes
1answer
95 views

What do the parameters at the top of an FCIDUMP file mean?

A while ago I wrote a simple program that takes in an FCIDUMP file (generated by MOLRPO) and can determine matrix elements (or ...
9
votes
1answer
79 views

What software can do RNA secondary structure prediction?

This question is a follow-up to this previous question. I have learnt there that there are reasonable ways to predict RNA tertiary structure. Here I inquire about how to predict RNA secondary ...
9
votes
1answer
64 views

What software is a software for RNA tertiary structure prediction?

It seems that the prediction of protein folding is a pretty advanced area. Are there options based on some GDT-like measure? For me, it has relevance in connection with the origin of life (cf. RNA ...
31
votes
5answers
3k views

What is a good replacement for Gaussian?

When I started studying computational chemistry (circa 2007), my supervisor used to tell me about the controversy surrounding Gaussian, Inc. regarding the banning of researchers involved in the ...
9
votes
1answer
179 views

How to calculate FCI matrix elements from an FCIDUMP file

I'm interested in writing a simple program (as an exercise) that takes an FCIDUMP file (e.g. from a Molpro calculation) and can determine FCI matrix elements (e.g. to construct the entire FCI matrix ...
21
votes
5answers
4k views

What software will allow me to combine two images?

I have seen in many presentations and publications, things like a human on a molecule (for example). What software can do this? It's for a presentation I'm doing.
10
votes
2answers
141 views

Programs/Libraries for calculating solvent excluded surface and excluded volume

Given the 3D structure of a molecule (e.g. as *.mol) and a probe radius r, I want to calculate the solvent excluded surface (SES)...
10
votes
1answer
117 views

How to determine occupied and closed orbitals for a Molpro CASSCF calculation?

I am currently working with Molpro, to which I am completely new, trying to run some calculations on $\ce{PdO}$. From literature I have gathered that the ground state is given by $^3\Sigma^-$ state, ...
8
votes
0answers
50 views

What could be the possible causes of the energy difference in the following calculation using Octopus (TDDFT) code?

I am trying to do a simple ground state energy calculation of methane molecule using the Octopus (TDDFT) code. The example is already available in the octopus manual. ...
9
votes
1answer
157 views

How are molecular orbitals constructed from the coefficients and basis set?

When an SCF calculation is done in a QM program, the MO coefficients of the solution are printed into the output. Now, graphical softwares can plot 3D molecular orbitals from these coefficients, ...
7
votes
1answer
36 views

The number of long-range interaction pairs in Tinker

I tested MM calculation of a benzene molecule with Tinker. The following is the xyz file used for the input. ...
11
votes
3answers
760 views

How to build a nanocluster?

What are the software tools (if possible open source) or methods we can use for constructing a nanocluster, most preferably with high symmetry such as icosahedron, octahedron, cuboctahedron etc. ?
6
votes
1answer
61 views

Understanding QuantumEspresso Toolbox through Maestro

Anyone here uses Quantum Espresso through Maestro can tell me a bit more about the calculation panel setting: I understand that -npools option must be divisible by ...
7
votes
0answers
304 views

Is there any code for local-orbital ab initio tight binding molecular dynamics other than fireball? [closed]

I was searching for a local-orbital ab-initio tight binding implementation of molecular dynamics and Ive found a code called fireball. Ive tried to compile it but the code seems to be buggy and there ...
6
votes
1answer
57 views

Band structure output from Exciting - what are the X units?

I'm using Exciting Code to calculate some electronic band structures. Starting with the example of Si I get sensible output and can plot BAND.OUT and BAND-QP.OUT using PLOT-gwbands.py or directly in ...
6
votes
1answer
58 views

How to calculate Transport coeffiecients for 0 D systems?

I would like to calculate the thermal transport coefficients like Thermal Conductivity, Seebeck coefficient etc for thermoelectric 0 D systems (quantum dots, nanoclusters ..etc). For bulk materials, ...
5
votes
0answers
38 views

Interpreting Critic2 charge analysis in metallic systems

I'm using Critic2 software to perform post-processing of the charge density of metallic alloys. With the charge density obtained from the Self-Consistent-Field calculation (for that I'm using Quantum ...
10
votes
1answer
143 views

Calculating/Visualizing electronic density from orbital information written in the Molden format

I'm trying to obtain an electron density from orbital information written in the Molden format by the formula, $$ \rho(\mathbf{r}) = \sum_{i}^{occ} |\phi_{i}(\mathbf{r})|^{2}. \tag{1} $$ Is there any ...
11
votes
2answers
363 views

Recalculate atom positions to account for periodic boundary conditions

I have the output of a simulation done using Periodic boundary conditions (PBC), however, the atom positions have been resolved, i.e. there are atoms outside the PBC-box now. Is there a software/...
12
votes
1answer
100 views

Recent developments in QM/MM for Molecular Dynamics

I am looking for new QM/MM methodologies which have recently developed and implemented into MD packages. Any applications or molecular systems studies with these methods can be used as an example as ...
16
votes
2answers
427 views

What's the best way to compare two DFT codes?

What's the most efficient way to compare the two DFT codes in terms of computation time, basis sets (for example, one plane wave vs one atomic orbitals), functional performance, etc.?
10
votes
1answer
123 views

How to create a Potential Energy Surface in Chemcraft?

The Chemcraft website says that it is possible to create a potential energy surface. Nevertheless, it doesn't work for my Gaussian scan job. ...
11
votes
1answer
221 views

Calculating RMSF in VMD

As a part of my coursework I have to calculate root mean square of fluctuation (RMSF) of a protein trajectory over the last 5 nanoseconds of simulation. I have used the inbuilt ...
9
votes
1answer
453 views

Why do we need to build a supercell to use the DFPT in Phonopy interfaced with VASP?

The following passage about the merits of density-functional perturbation theory (DFPT) is extracted from this seminal paper: Phonons and related crystal properties from density-functional ...
10
votes
1answer
233 views

Generating SOAP descriptors in python

What is the best python package to construct Smooth Overlap of Atomic Positions (SOAP) descriptors given SMILES representation of a molecule? Is this even possible without providing 3D geometry? An ...
10
votes
2answers
101 views

Can you list some useful code snippets for processing quantum ESPRESSO output files?

I know that this is quite general. But we have all written code for processing output files from various dft codes. The functionality of which, may range from analysing time traces to finding ...
19
votes
2answers
417 views

What is a chemputer?

I first saw the term "chemputer" when reading about the work of Neil Ostlund (who you may know as one of the authors of the famous book "Modern Quantum Chemistry"). Based on the ...
10
votes
1answer
131 views

What are the trade-offs setting DIRSCF to either .TRUE. or .FALSE. (the default) in GAMESS (US)?

The first software I used to run calculations was Gaussian09. When submitting a input, I used to see a pattern of resource usage where the allocated CPU quickly maxed out, remaining high most of the ...
6
votes
1answer
72 views

How better is PAW available in VASP when compared to that present in PS Library?

Papers with DFT calculations that use VASP work with PAW pseudopotentials which are also available in PS Library. I assume they are different since VASP is commercial. Given that, how different are ...
7
votes
2answers
972 views

Computer simulation of squeezing flexible objects with force

I am looking for any software, or scientific works, or search phrase in the field of simulating graphic modeling of squeezing objects. I would like to simulate packing very oddly shaped soft elastic ...
5
votes
1answer
31 views

What are some ways to model disequilibrium processes with current software?

Its normally that case that most material modeling techniques rely on energy minimizations, which result in the equilibrium solutions for most chemical of physical processes. While this is great for ...
8
votes
1answer
77 views

What software can perform block analysis on time sequence data?

I have a .xyz file for a trajectory and I want to perform block analysis on it, and to find the decorrelation time and to perform analysis on that as well. What ...