Questions tagged [software]

For questions pertaining to software used by chemists for professional or academic purposes.

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24 views

Sources for files for testing a thermal ellipsoid (ORTEP) program

I am trying to reimplement the functionality of the classical program ORTEP for producing thermal ellipsoid plots of a crystal/molecule in a modern computer language. Unfortunately, I am having ...
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0answers
46 views

How to extract force constants for normal modes from ORCA?

I am following the computational method described in Scientific Reports.[1] Where the authors analyze the contribution of each excited state normal-modes to the shift of the transition energy. For ...
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1answer
68 views

Software that determines whether a molecule can exist and draw it from a formula?

I have run calculations that predict atomic configurations. As a simple example, in a system that contains H and O, I might get a list like: ...
5
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2answers
52 views

Freely available software for generating 3D coordinates of molecules

As part of some research I am doing, I want to do a head-to-head comparison of software for generating 3D atomic coordinates for molecules. Is there a list anywhere of chemical software that does this?...
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90 views

OpenBabel: how to get correct SMILES from Gaussian output?

I would like to get the molecular structure as SMILES from Gaussian output files. OpenBabel seems to be the tool made for such tasks. However, the structure is not always correct. One example: ...
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1answer
38 views

Red Squares in RDKit?

I'm newish to RDKit and couldn't find an answer to this online. The following is a minimal representation of how I drew a molecule ...
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0answers
275 views

Cloud-based molecular modeling software

I’m an IT Acquisitions and Licensing specialist researching well-supported cloud software alternatives to Fujitsu’s molecular modeling SCiGRESS. I am coming in with a tech background, but little to ...
5
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1answer
72 views

Why does the SCF not converge in a structure optimization with GAMESS of the thiourea molecule at the PM6 level of theory?

I'm using GAMESS to run a geometry optimization on a thiourea molecule, using PM6. However, the output file keeps displaying the error message, "NO FORCE FIELD, SCF DOES NOT CONVERGE." Is there an ...
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1answer
22 views

How do I calculate the proportion of respective conjugates of one base mixed with several acids (and/or conversely) at different temperatures? [closed]

How do I calculate the proportion of respective conjugates of one base mixed with several acids (and/or conversely) at different temperatures, and is there a free software tool that would allow me to ...
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1answer
31 views

Is there a way to export detailed data about atom connectivity, dihedral angle, etc from GaussView?

As far as I know, opening the .com files as .txt files (with a text editor like simple notepad) yields a nicely formatted table ...
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2answers
141 views

Software or library for creating images of ball and stick models?

Is there any code library (in any programming language) or software capable of producing images of ball and stick diagrams? Example of an image of a ball-and-stick model for Ammonia: (Image source) ...
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1answer
157 views

converting SMILES (or .mol2) to SMARTS

The conversion between different chemical structure formats, e.g. from .mol2 to .xyz, by openbabel may tied to conditions to be met. One example of such a filter is to allow such a conversion only ...
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0answers
31 views

Rotating dihedral and Angles And Generate File For Each Degree

I need to optimize a force field I generated. For this, I should apply Genetic Algorithm (G.A). To apply G.A I should do this for 220 molecules: 1) Find all dihedrals for each molecule ( I did this ...
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48 views

Software for computations of rovibrational states' energies and corresponding spectroscopic constants in diatomic molecules

I need to compute rovibrational energy levels and also the spectroscopic constants, especially $\omega_e$ to compare my results with other papers. So far I've tried LEVEL16, which seems very ...
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0answers
104 views

DFT Exchange-Correlation Two Electron Integrals

Are there any electronic structure programs that print the exchange-correlation (XC) integrals for a given DFT functional? These integrals are of the form $$\langle pq|w|rs\rangle$$ where $w$ is an XC ...
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0answers
38 views

How to obtain spectroscopic constants Omega_e, Alpha_e, B_e, D_e and D_0 from centrifugal constants?

I need to compute a spectroscopic constants of $N_2^+$ states and I would like to do it using LEVEL16 software, due to its high interpolation flexibility. But it seems, that LEVEL16 can only compute ...
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0answers
55 views

ApexTrack: peak tail looks like a shoulder

I'm trying to implement ApexTrack algorithm in my software by following the description written by Waters. But many chromatograms that I see have noticeable tailing of peaks: . No matter what ...
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40 views

How can I save and read the CI vector during CASSCF calculations in Gaussian?

I have searched through the GAUSSIAN 16 manual and have not been able to solve these two related issues: (1) I want to be able to save the CI vector and load it as an initial guess for a different ...
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74 views

How to get the second electron affinity of tellurium?

I need the value of the second electron affinity of Te, i.e. the energy change associated with the attachment of an electron to a $\ce{Te-}$ anion $$\ce{Te- + e- -> Te^{2-}}$$ In the books (e.g. J. ...
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1answer
165 views

How to prepare a Gaussian input file for a binary solvent?

The UV absorption energy spectrum of a molecule has been recorded experimentally using binary solvent (DMSO:Water=9:1 v/v). I am trying to calculate the absorption energy of the same molecule using ...
4
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1answer
131 views

How to draw protonated benzene (horseshoe) carbocation structure with ChemDraw?

Is there a way to draw the aromatic "horseshoe" (forgot the official name) structure of a protonated benzene cation (arenium) with ChemDraw, and not the cation with double bonds?
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1answer
246 views

Gaussian syntax error on the input line

I ran a Gold complex in Gaussian 09 with the following exact Route Section PBE0/LANL2DZ Opt Freq NoSymm and it gave me this error message: ...
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1answer
56 views

Help with missing output from cubegen utility after density calculation in Gaussian16

I am busy trying to do density calculations in Gaussian16 as I need the .cube output for input to the PIXEL software. But my Gaussian output seems to be missing an entire chunk of data and I don't ...
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2answers
155 views

Molecular orbitals used with CCSD(T) geometries

Suppose I am given some geometry data (say, of a water dimer) from CCSD(T). If I were to do a single-point energy calculation to generate orbitals for the system, wouldn't CCSD give something more ...
4
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1answer
548 views

Illustrator to chemdraw [closed]

I am not sure that this is the right place for this question, but I'll try. I am working on a scheme that I am developing on illustrator. I have a lot of chemical structure and plus I have some ...
3
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1answer
61 views

Why is the ROHF spin density of the propenyl radical not symmetric?

I was preparing some material for my students and in order to illustrate the concept of spin density and how the ROHF method gives a purer description of this property than the UHF method. I prepared ...
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94 views

Ab initio MD simulations in VASP

I'm not sure if this is an appropriate question for Chemistry.SE, but I'm taking a stab. I'm running ab initio MD calculations in VASP and I'm trying to optimize different input tags. On the VASP ...
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2answers
133 views

What library/program can draw molecules in 3D programmatically?

Molecular graphics software is usually interactive. But I am looking for a library or program that would be able to render a given molecule based on the commands from another program. I would like to ...
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2answers
228 views

How To Scan “improper dihedrals” in Gaussian 09?

I am trying to parameterize Amber force field for a novel molecule, but I couldn't obtain improper dihedrals. Because if I scan impropers like dihedrals; later or sooner the molecule is overlapping ...
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0answers
53 views

Generating density matrix of a wavefunction from common quantum chemistry software

I am looking for density matrixes for a couple of closed shell and open-shell systems, and I wonder if there is a trivial way to make e.g. Gaussian just generate an output for me. I may be wrong but ...
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0answers
40 views

Geometry optimisation in Gaussian09

I have looked at various sources regarding this, including the Gaussian official website. However, I have not managed to understand the geometry optimisation method used by Gaussian, a method known as ...
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1answer
69 views

Software for the atom model of all elements [closed]

I want an atom model with shells but I haven't found one yet and the only software that created an atom was Cinema 4D. This software is not for beginners like me and I used a tutorial to make an atom ...
4
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1answer
206 views

Raman spectra in Gaussian [closed]

I want to simulate Raman spectra of benzene in Gaussian 09. Calculated spectra for a single ring Benzene ($\ce{C6H6}$) in Gaussian differs about $\pu{40 cm^{-1}}$ for each peak, compared with ...
3
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1answer
76 views

Is there a way to check reactions? [closed]

I'm very new to organic chemistry. I would like to practise simple reactions (HX + Alkenes, X2 with Alkenes and so on) with examples i create myself. Is there a way to check if my products are ...
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1answer
71 views

ChemDraw temporary label for chemnum LaTeX

Currently I'm searching for a nice way to implement my ChemDraw graphics into $\mathrm{\LaTeX}$. There is a package called chemnum which will auto-label the ...
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1answer
120 views

Molpro - Connection between atomic term symbols and system symmetry

Let's say I have a carbon atom with the electron configuration $1s^22s^22p^2$. We know, that using atomic term symbols we can describe the following states: $${}^3P_0, {}^3P_1, {}^3P_2, {}^1D_2, {}^...
3
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1answer
58 views

Why is the active space for the dinitrogen cation defined this large in my example?

I have a Molpro script which computes $\ce{N2^+}$ potential energies. The significant part is the input for the wave function: ...
2
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1answer
62 views

How do I have to interpret the input to the OCC flag in Molpro?

I'm trying to understand the occupied orbital specification in Molpro. They're specified by the OCC flag, while it's stated in the documentation, that OCC, m1, m2, ..., mn; where the ...
3
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1answer
157 views

Molpro - Simple explanation of OCC, CORE, FROZEN and CLOSED orbitals

I'm beginning with quantum chemistry and I'm supposed to do some ab initio calculations with Molpro. The problem is, I don't understand the orbital specification very well. Let's say, I have the ...
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1answer
224 views

How to type condensed formulas in ChemDraw?

What I want is shown in the bubble 1, while what I keep getting every time I change the single bond to a double bond is shown in bubble 2. The H of the middle C in bubble 2 keeps shifting down when I ...
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0answers
129 views

Restarting a Gaussian partially constrained relaxed surface scan using GICs

I am Using Gaussian 16 rev D.01, and I want to perform relaxed surface scans where I vary a bond distance. At the same time I constrain seven atom coordinates during the entire optimization (this is ...
4
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1answer
1k views

How to use dispersion correction with TPSSh in Gaussian 16?

A colleague of mine suggested to use TPSSh as a functional. Since I am applying Grimme's D3 dispersion correction by default, I was surprised that it wasn't implemented in the standard density ...
3
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1answer
34 views

Automated Identification of Isomeric Relationship from 3D Structure?

Is there a software package that when given two sets of 3D structures can return the isomeric relationship between them? Even if it was only able to state that they are conformational isomers that ...
5
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1answer
128 views

How can I recognize aromatic rings in a connection table?

Given a connection table (that is, a list of atoms, their connectivities/bonds, and the type of bonds), how can I detect the presence of an aromatic ring? For reference, the aromatic rings in the ...
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0answers
169 views

How to interpret Gaussian output for excited states?

I have calculated the excited energies for benzene in Gaussian. The output therefore was: ...
10
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0answers
328 views

Understanding two-electron integrals in Gaussian 09

I was comparing the two-electron integrals (electron repulsion integrals, ERI) printed by various well-established packages (Gaussian, GAMESS, Molpro etc.) and observed that Gaussian is the oddball in ...
3
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2answers
101 views

Is there a piece of software that can help me see the (hkl) planes in a crystal lattice?

I am doing research with calcium carbonate structures. I need a way in which I can familiarize myself with the lattice structure of calcium carbonate polymorphs, especially calcite. I really struggle ...
1
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1answer
41 views

How to display ligands as ball and stick and macromolecules as cartoons (if protein) / rings (if nucleic acids) in Avogadro?

Avogadro has many good qualities but I can't seem to find a way to display ligands differently to macromolecules in the same view window. Frankly I can't seem to find a way to display any two things ...
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3answers
66 views

How to calculate number of each type of atom in a residue in PyMOL?

I have a 3D model of PDB 4UDC (dexamethasone bound to human glucocorticoid receptor), and I'd like to calculate how many atoms of each element are in the dexamethasone molecule (which has the residue ...
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0answers
78 views

How does the “sample type” selection on the MassHunter software for Agilent 7900 ICP-MS affect the quantitative results?

I'm new to using the instrument, and recently I have tried to measure Cr in both the eluent(1% nitric acid) and a method blank (also 1% nitric acid, but after it has gone through the entire analytical ...