Questions tagged [orca]
For questions about (or involving) the ORCA electronic-structure package.
67
questions
2
votes
1
answer
34
views
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:
...
- 21
5
votes
1
answer
62
views
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 ...
- 255
4
votes
1
answer
344
views
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 ...
- 4,687
3
votes
1
answer
112
views
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.
3
votes
1
answer
85
views
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:
...
2
votes
1
answer
41
views
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:
...
4
votes
0
answers
72
views
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 ...
- 6,436
4
votes
0
answers
33
views
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 ...
- 6,436
4
votes
1
answer
112
views
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 ...
- 870
4
votes
0
answers
80
views
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 ...
- 41
5
votes
1
answer
295
views
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 ...
- 141
5
votes
1
answer
130
views
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 ...
- 327
7
votes
3
answers
2k
views
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 ...
- 165
3
votes
1
answer
212
views
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 ...
- 173
3
votes
1
answer
171
views
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:
...
- 173
5
votes
0
answers
112
views
ORCA failed during NEB-TS ONIOM
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 ...
- 51
5
votes
3
answers
326
views
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?
...
5
votes
1
answer
392
views
Numerical Evaluation of Hessian?
I am trying to understand the construction of Hessian matrix using numerical differentiation (NUMFREQ option in ORCA for example). I understand that Hessian is a square matrix containing second ...
- 2,612
1
vote
0
answers
45
views
How to obtain the expectation values of spin operators in ORCA
I want to obtain the expectation values of the spin operators $<S_{x}^2>$, $<S_{y}^2>$ and $<S_{z}^2>$ from a CASSCF calculation in ORCA. Is there a way to directly print them into ...
2
votes
0
answers
28
views
How to handle explicit solvent molecules when calculating energies of reactant molecules in isolation
When determining the energy barrier, it is recommended to compute the energies of reactant molecules in isolation to account for the entropy change of forming the reactant complex (hence factoring ...
- 131
3
votes
0
answers
590
views
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 ...
- 131
6
votes
1
answer
122
views
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 ...
- 173
4
votes
1
answer
385
views
Optimise S1 geometry with CASSCF in ORCA
I'm trying to optimise the excited state of benzene using ORCA 5.0.1 software.
I've already optimised the $S_0$ geometry with CAS-SCF[6,5] with the following input file
...
4
votes
1
answer
174
views
How does ORCA treat intermediates in Nudged Elastic Band (NEB) calculations
I'm trying to run a quite complicated NEB optimization with (hopefully) one intermediate structure.
But before losing time, I was wondering:
how does ORCA treat that intermediate?
does ORCA optimize ...
6
votes
1
answer
261
views
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:
...
- 61
4
votes
1
answer
221
views
How many electrons and orbitals should I include in a CASSCF calculation?
I'm interested in running CASSCF calculations to get a dissociation curve for a number of systems of the form: atom-atom, atom-diatomic or diatomic-diatomic (e.g. Li+ ... O-, K+ ... O2, or N(3-) ... ...
- 801
5
votes
0
answers
97
views
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 ...
5
votes
0
answers
72
views
Does a TD-DFT excitation from a closed-shell determinant only include the alpha electron part?
From an input in ORCA 5.0.3
! PBE 6-31G*
%TDDFT NROOTS
3
END
* xyz 0 1
H 0. 0. 0.
H 0. 0. 0.7414
*
the output includes
...
- 51
4
votes
1
answer
103
views
Recalc entropy and free energy from scaled hessian
I have already performed a FREQ calculation on my system. Following the manual, I then changed the scalar factor accordingly to the theory level I've done my calculation.
As procedure suggested in the ...
4
votes
0
answers
2k
views
ORCA finished by error termination in SCF gradient [closed]
I try to optimize and compute frequencies for the system built up from C, O, H, and Co atoms in the following functionals: B2PLYP, B2PLYP-D3, B3LYP, B3LYP-D3, BLYP, BLYP-D3, DSD-PBEP86, PBE, PBE-D3, ...
user1247
8
votes
1
answer
187
views
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 ...
5
votes
1
answer
254
views
Successfully running parallel gas phase calculation on AMD cloud instance but implicit solvent fails (Local Intel workstation successfully runs both)
I am using an AMD Linux cloud-based instance to ran general optimisation and transition state calculations in parallel. I have noticed that I can run gas phase calculations in parallel but the run ...
- 131
5
votes
2
answers
456
views
7
votes
1
answer
256
views
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 ...
- 327
5
votes
1
answer
412
views
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.
...
5
votes
1
answer
255
views
ORCA: CIS calculation for Helium atom
I want to understand ORCA output for CIS calculations.
From the input file
...
- 357
6
votes
0
answers
499
views
MOLDEN file from ORCA output
I'm trying to convert an ORCA output file into MOLDEN file (via molden itself).
I hit the "Write" button and it converts the file, yes, but the displacement vector s are zeros. I need that ...
4
votes
1
answer
307
views
ORCA: meaning of numbers in ORCA.out of MOLECULAR ORBITALS for STO-3G Lithium
For Lithium STO-3G basis set
...
- 357
4
votes
1
answer
254
views
Non-equilibrium CPCM for Orca Absorption Spectra
I run into this article[1] in which they figure out that if you want to correctly simulate electronic spectra you have to consider the non-equilibrium solvation.
I've made research into the ...
3
votes
0
answers
356
views
Segmentation fault with ORCA-3.0.1 [closed]
I would like to use ORCA-3.0.1 under the following Linux version:
5.10.0-10-amd64 #1 SMP Debian 5.10.84-1 (2021-12-08) x86_64 GNU/Linux
and Intel version ...
- 343
3
votes
0
answers
453
views
STEOM-DLPNO-CCSD [closed]
I have to calculate the S1 - T1 energy gap using coupled cluster (STEOM-DLPNO-CCSD) in ORCA. The output file contains only singlet energies.
IROOT=... (no notation singlet or triplet).
I tried adding &...
7
votes
2
answers
1k
views
Different types of transition dipole moment in ORCA output
In the ORCA output for a TD-DFT calculation, there are two types of spectra printed. One is called "transition electric dipole moment" and "transition velocty dipole moment".
...
- 6,436
7
votes
1
answer
625
views
What are the output files generated by an NEB calculation?
I just used Orca for the first time.
Can someone address me a valid guide to understand all the files in the directory?
I'd like to perform a Nudged Elastic Band (NEB) calculation, but I'm stuck ...
7
votes
1
answer
166
views
Is It possible to do microkinetic modelling for liquid phase reactions, in the presence of a catalyst?
As from the title, I want to do NEB-TS for chemical reactions in the liquid phase, and use the information to calculate reaction rates/kinetic rates.
I know that the NEB-TS is possible in the liquid ...
5
votes
1
answer
778
views
Unrecognized or duplicated keyword error using ORCA
I wanted to run ORCA 5.0.2 with the following input:
...
- 343
6
votes
0
answers
480
views
How do you perform parallelization of NEB-TS in ORCA? [closed]
I have tried running a NEB-TS calculation in orca with %pal nprocs 32, but I get an error saying ...
- 61
7
votes
1
answer
3k
views
How to properly define %maxcore in ORCA
The %maxcore parameter in ORCA gives the memory per core needed for a calculation, however it is unclear to me if this should be the entire memory available to the ...
- 10.7k
7
votes
1
answer
467
views
Numerical Frequency Parallelization in ORCA
In orca it is possible to use NumFreq and AnFreq to get the numerical and analytical frequencies, but the analytical frequencies take a large amount of memory and computing time compared to numerical ...
- 10.7k
5
votes
1
answer
563
views
Modify ORCA orbitals for CASSCF
I have run a HF calculation on naphthalene and I have checked the MOs that have been obtained. Now, I have to select my active and inactive orbitals for CASCF(10,10). As there are 34 occupied orbitals,...
- 967
13
votes
3
answers
425
views
Quantum chemistry in external electrostatic field?
Which quantum chemistry methods can be used in an external electrostatic field? Also which software supports that? I'm interested in anything from semiempirical (eg XTB) to DFT (eg ωB97, B3LYP-D3) ...
- 801