Questions tagged [orca]
For questions about (or involving) the ORCA electronic-structure package.
91 questions
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How to plot orbitals for S1->T1 transition in Orca
I use TD-DFT and want to examine how molecular orbital changes upon ISC from S1 to Tx state and refer to confirm El Sayed rule. How to achieve it if NTO are not generated for S1->Tx transitions? If ...
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2
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589
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What is the difference between actual energy vs scf energy in an orca scan
Always at the end of the output of a scan type calculation in orca there are two tables one with the name "The Surface Calculated using the 'Actual Energy'" and the other "The Surface ...
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1
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Why is my sum of squares of molecular orbital coefficients not 1.0?
I was hoping the sum of squares of molecular orbital coefficients to be 1.0, but alas this is not the case. The occupancy of these orbitals is given as 2.0 . These coefficients were output by both ...
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1
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1
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179
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Problematic optimization of excited states
I work with Orca 5.0.4 (without access to version 6.0) on a symmetric metal-centered system. I'm currently running excited state optimizations, and while S1-S3 and T1, T2, and T4 have optimized ...
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6
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255
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Assessing excited state lifetime with TD-DFT
My question is brief — is it possible to estimate excited state lifetimes using computational chemistry (DFT/TD-DFT) tools? I am aware this may be a rough approximation (e.g., neglecting non-radiative ...
- 10.2k
3
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How can the singlet wavefunction be used for a triplet calculation?
I am performing a single-point calculation in ORCA to determine the singlet excited state energies. I also want to calculate the triplet state energies, but I've noticed something that seems incorrect....
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3
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1
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122
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Dipole moment of electron-attached state in ORCA EA-EOM-CCSD
I am trying to calculate the electric dipole moment of some (neutral) doublet molecules using ORCA 5.0.3. The molecules of interest have a nice interpretation as having 1 electron attached to a closed-...
CommunityBot
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94
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Obtain force constants from normal modes
I am trying to reproduce an QTAIM analysis by Foroutan-Nejad et al. (https://chemistry-europe.onlinelibrary.wiley.com/doi/full/10.1002/chem.201402177). Instead of only looking into the equilibrium ...
- 1,591
3
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Mixing functionals in TD-DFT opt
I work with copper complexes containing at least 100 atoms (including a single Cu, nitrogens, carbons, and hydrogens). According to Grimme's paper, the benchmark level for geometry optimization is ...
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IRC calculation shows a maximum in one direction
I am doing IRC calculations on transition-states of organometallic compounds with ORCA. While I only find one imaginary mode for the transition state which corresponds to the expected vibration, ...
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ORCA 6 slower than ORCA 5?
Has anyone else noticed that ORCA 6 is behaving slower than ORCA 5? For example, if I run the simple test job:
...
- 156
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3
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Different results from MP2 calculations on same geometry in ORCA
I am trying to do a segmented potential energy scan around a dihedral for a molecule. I have optimized the geometry to a minima, and the scan runs from [-180, 180] in steps of two points at a time.
...
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129
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What would be the best tool to simulate FTIR spectra of molecules?
I tried to simulate a spectrum of a porphyrin using the orca 5.0.4 program, calculating the frequencies and simulating the spectrum with the orca_mapspc program from the orca package, however the ...
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Do oscillator strengths matter when matching theoretical and experimental outcomes?
I use ORCA to do TD-DFT studies. The experimental maximum absorption is esteemed to 445.0nm . Benchmark computations were conducted and this is the exemplatory (part of) the output:
...
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Should I use ZORA/DKH for my geometry optimization, or only for TD-DFT?
ORCA has implemented a scalar relativistic contracted version of def2-TZVP (with DKH or ZORA), which I used to study a copper-phenantroline system (for geometry optimization and TD-DFT).
My question ...
9
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QuasiRRHO in Orca
I read that ORCA runs a QuasiRRHO calculation based on Grimme approximation, at the end of a freq calculation.
Unfortunately, I wasn't able to find the default value for the CutOffFreq. In Grimme's ...
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23
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What is the largest system that has been studied by the coupled cluster method?
This is parallel to the analogous question about the largest DFT calculation: What is the largest material that has been studied using density functional theory?
I assume we allow high performance ...
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Cannot reproduce excitation energies in Orca
I do TD-DFT studies in Orca 5.0.3 on porphyrin system and hence at the very beginning I need to pick functional that reproduce excitation energies.
The experimental reported values equal: 691, 656, ...
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95
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How to calculate Gibbs free energy of a reaction involving cations using GFN2-xTB (via ORCA)
I am trying to compare the Gibbs free energy of reactions such as:
A + 4K(+) --> B(4+)
A + 4Na(+) --> C(4+)
A + 4Li(+) --> D(4+)
A + 4Ca(2+) --> E(8+)
A + 4Mg(2+) --> F(8+)
In these ...
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322
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OpenMPI not running under SLURM in UBUNTU with ORCA?
I have ORCA 5.0.4, OpenMPI 4.1.1 and SLURM in UBUNTU 22 in a single PC with 16 threads.
I have setup this pc and, when I run orca alone, openmpi works. But, when I submit orca through slurm, the ...
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6
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2
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754
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Bromine basis set problem
I'm trying to compute the energy of the benzyl bromide with orca. I need it to be at ωB97x-d4/6-31g(d) level. Orca throws me the following error.
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- 151
2
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219
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Error: Cannot open GBW file: TS.gbw
I have a problem with calculating Transition State using NEB-TS. Here is my input file:
...
- 7,171
5
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2
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374
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Trying to get concurrent results for a TDDFT calculation in Gaussian and ORCA
I am trying to do a simple TDDFT calculation in both Gaussian and ORCA from the exact same reference Geometry. I am using the same functional (making sure to use ...
- 196
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How to generate .47 files from ORCA-5.0.3 ? Also, can we analyze the second order perturbation energy analysis within the nbo scheme using GENNBO?
I am using ORCA-5.0.3 as ESS package and our group has also recently purchased nbo7 which is not interfaced with the ESS. I had tried multiple ways to generate .47 file but couldn't succeed and am ...
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Mathematical model/open source code to obtain displaced geometries along a normal mode from vibrational frequency calculation
I am looking for a mathematical model which will produce the displacement vectors from vibrational frequency calculations. I use ORCA for the calculation of the frequencies and generally use Chemcraft ...
CommunityBot
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1
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589
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Syntax Error in ORCA
I keep getting the following error for my orca code:
[file orca_main/maininp1.cpp, line 17547]: ERROR: expect a '$', '!', '%', '*' or '[' in the input
[file ...
- 495
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2
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166
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Reintegrate calculation results from ORCA using finer grid?
I have made a bunch of calculations in ORCA to compare them to results from this paper. The original calculations from this paper were done in TurboMole. I tried to recreate the method as best I could ...
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ORCA: Getting the error "mpirun noticed that process rank 0 with PID 383161 on node exited on signal 11 (Segmentation fault)."
I am getting a segmentation fault error when running the following input file below. The calculation runs fine in gas phase and CPCM modes, but fails with SMD. What could be the issue? Some are saying ...
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1
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UseSym Keyword in ORCA fails to find appropriate number of SALCs
I am trying to run some geometry optimizations in ORCA 5.0.4 and I am using the UseSym keyword to ensure that my molecules retain Cs Symmetry during optimization. ...
- 10.2k
7
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1
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319
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Do ORCA input files allow for multi-line comments or different comment syntaxes?
I have a self-inflicted problem with the input files that I am generating using RDKit in order to automate my ORCA jobs. I like to keep track of data such as:
The ...
- 1,056
5
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1
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527
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ORCA crashes because of RI approximation?
I am doing a geometry optimization for a cationic imidazolate-zinc complex.
I'm trying to run an optimization using this input file. It uses the RI approximation.
ORCA seems to be running fine until ...
- 521
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210
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ORCA Error: NCalcs not set
I've been getting the following error whenever I use CCSD(T) and the ORCA Forums don't have an answer to this one:
...
- 10.2k
4
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1
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527
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Kill or let be: Is this calculation stuck or just very slow?
My question is regarding a medium-to-large DLPNO-UCCSD(T)-F12 calculation.
I have a ~250 electron system, an open-shell molecule inside a water droplet, and I'm trying to get the total energy, first ...
4
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1
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449
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Calculating Reorganisation energy using ORCA
I wondered if anyone knows of a way to calculate the reorganization energy of a molecule utilizing orca 5.0.3.
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Repeated Error message ORCA
I am repeatedly getting the error message:
[file orca_main/maininp1.cpp, line 17547]: ERROR: expect a '$', '!', '%', '*' or '[' in the input
when I run my Orca script.
My inp file looks like:
...
- 4,066
2
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1
answer
365
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Calculating vertical excitation energies at the DLPNO-STEOM-CCSD Theory level
I want to calculate the vertical excitation energy using the DLPNO-STEOM-CCSD method, on molecules previously optimized using TD-DFT. the parameters being used are as follows:
...
- 10.2k
5
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327
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How to calculate singlet-triplet splitting energy with TD-DFT in ORCA?
I wish to reproduce the results from this paper by Truhlar and co-workers, where they treat a spin-forbidden reaction by considering two effective states coupled by a semi-empirical spin-orbit ...
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How to compute only part of molecular Hessian accurately (hybrid Hessian or partial Hessian calculation)?
Hessian is required for minimisation and transition state (TS) optimisation algorithms. While the full Hessian at a certain level of theory is calculated usually for TS optimisation, usually ...
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926
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Running multinode parallel Orca calculation without a work load manager (scheduler)
I wonder, if someone has run (runs) parallel Orca calculations on at least two nodes without a work load manager (scheduler)? I am asking because I have several interconnected servers (nodes) I'd like ...
4
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1
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Question on CPU timings and/or ratio resp. DLPNO-CCSD(T) and wB97X-2-D for protein of ca. 1M Da
Suppose one has a protein of about 1 million Da, and performs a DLPNO-CCSD(T)/def2-TZVPPD/AutoAux/AutoAux calculation, and then performs a wB97X-2-D/def2-TZVPPD/AutoAux/AutoAux calculation, both via ...
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orca_vpot problem
I'm trying to calculate the electrostatic potential of a molecule. When I try to use the orca_vpot tool, I am facing some difficulties detailed below.
The first ...
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Does it make any sense to run a TD-DFT calculation with Finite-Temperature SCF active?
I recently received the task to investigate what is happening in a fluorescent molecule in different temperatures. How the electronic population is changing and how is this affecting the electronic ...
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3
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753
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Energy of each fragment in ORCA?
After the definition of the fragments in the geometry section of the calculation, is there a method to call, or a keyword to turn on, in order to obtain the energy of the fragments themselves?
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- 1,009
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Running an ORCA calculation from Python
I'm a master's student and recently I started doing computational chemistry calculations using ORCA program.
This program works by command line and I saw that the majority of computational chemistry ...
7
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1
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317
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Simulating autoionization of small molecules using DFT or AIMD
From what I'm reading, simulation of auto-ionization in liquid substances is hard to do using gas phase DFT or AIMD [1][2][3]. I am using ORCA to do my work and I must confess that I'm shocked to see ...
6
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1
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Is it possible to restrict the calculation of frequencies in ORCA program?
I looked in the orca manual but didn't find anything, but in the case of having a molecule adsorbed in a cluster, is it possible to perform the frequency calculation only on the molecule and not on ...
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How to scan Improper Dihedral in Orca? [closed]
I am using Orca 4.2.1 for the ab initio calculation. Scanning the redundant coordinates I am trying to scan potential surface for different type of bonds, angles and dihedrals. How can I do so for ...
- 3,155
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894
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Unrecognized or duplicated keyword error using ORCA DFT calculations using avogadro
I'm using Avogadro to generate an input for ORCA, however, when I'm trying to run that input in ORCA it says:
...
- 3,155
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1
answer
646
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Orca calculation with scan error related with auxiliary basis
I'm trying to do a SCAN calculation in the ORCA program version 5.0.3 in which, at a certain moment of the carbon-carbon bond breakage, the following error message appears:
...
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ORCA failed during NEB-TS ONIOM [closed]
Thanks in advance for any help provided. I was trying to find the transition state of a diels alder reaction and considering my system's bulkiness I wanted to try a NEB calculation considering part of ...
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