All Questions
Tagged with orca quantum-chemistry
19 questions
4
votes
0
answers
60
views
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 ...
- 563
3
votes
1
answer
61
views
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 ...
- 33
5
votes
1
answer
88
views
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:
...
- 563
8
votes
3
answers
411
views
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.
...
- 4,066
2
votes
1
answer
210
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:
...
- 63
4
votes
1
answer
527
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 ...
- 4,899
3
votes
1
answer
1k
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:
...
4
votes
0
answers
94
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 ...
- 7,171
5
votes
0
answers
255
views
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 ...
- 51
5
votes
3
answers
754
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?
...
- 1,009
6
votes
1
answer
894
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
0
answers
3k
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, ...
- 51
5
votes
2
answers
813
views
4
votes
1
answer
518
views
ORCA: meaning of numbers in ORCA.out of MOLECULAR ORBITALS for STO-3G Lithium
For Lithium STO-3G basis set
...
- 357
3
votes
0
answers
705
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
5
votes
1
answer
1k
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
761
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
12
votes
3
answers
702
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) ...
- 1,250
8
votes
1
answer
2k
views
How to get the .47 file from ORCA for natural bonding orbital analysis
I am trying to perform NBO analysis with relaxed density matrix with the open-source program JANPA. I am following the guide here. The first step is to get the NBO input .47 file from Orca v4.2.1. The ...
- 7,171