Questions tagged [casscf]
For questions about performing Complete Active Space Self Consistent Field calculations
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Spin Configuration of Active Space in PySCF
I was running a state averaged CASSCF (4,4) calculation for the first 3 roots of the TMM biradical in PySCF. I wanted to get the spin configuration of the active space but the only information I could ...
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Table of Largest CI Components in PySCF CASSCF Calculation
I was running a simple CASSCF calculation in PySCF on the TMM biradical. It was a CASSCF (4,4) state averaged calculation where the energies of the first 3 roots were calculated. The simulation output ...
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Choosing an active space for CASSCF using Molpro
I am trying to determine the potential energy curves for a CH2Cl radical by varying the C-Cl distance. For that I use the CASSCF method In MOLPRO with the aug-cc-pVTZ basis set, I didn't get smooth ...
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How to choose the number of roots in a CASSCF calculation?
What are the criteria that one has to consider while chosing the number of roots in a CASSCF calculation?
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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-) ... ...
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Setting a frozen core in Molpro
I am carrying out a project which involves obtaining the RHF result and the integrals for the chromium dimer (Cr2) under Ahlrichs' SV basis. In the literature against which we attempt to benchmark, ...
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Which molecules have multi-reference character?
I'm using WebMO to construct molecules that have high multireference character, but I cannot seem to find any, or perhaps I'm not building them correctly on WebMO; I know singlet biradicals generally ...
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Open source FCI solvers for exact diagonalization of the many-electron Hamiltonian
What open source solvers (according to the generally accepted Open Source Definition i.e. licensed under a valid open source license) are available for full configuration interaction calculations? ...
- 18k
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Frequency error in Gaussian CASSCF(10,10)
I am stuck in calculating the frequencies of one optimised geometry for naphthalene CASSCF(10,10) with Gaussian 16. I have optimised its geometry and checked the active space is the pi system of it, ...
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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,...
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Molecular orbitals and active space
During the same minute as asking this question, I also asked this at Quantum Computing SE.
In Qiskit, each qubit corresponds to one spin orbital. For example, the $\ce{N2}$ molecule would have 10 ...
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Calculating wave-function overlap in MOLPRO
Is it possible to somehow calculate the inner product (or overlap) between the electronic wave-functions of excited states in Molpro? What I want to do is to compare the electronic wave-functions that ...
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In Molpro, how to calculate the orbital angular momentum?
I wish to calculate the values of the orbital angular momentum of excited electronic states, using Molpro. So $\langle L_x \rangle$, $\langle L_y \rangle$, and $\langle L_z \rangle$. (Specifically for ...
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How does MOLPRO choose active orbitals in a CASSCF calculation?
I am trying to calculate electronically excited states for the CO molecule, with the aug-cc-pVTZ basis set, and a CASSCF calculation. The documentation describes ...
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CASSCF and thermochemistry—effect of excited determinants on rotational and vibrational modes
So this question is linked to the other question I asked about the electronic patition function and CASSCF. When calculating thermochemical data (e.g. Gibbs Free energy) the partition functions are ...
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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 ...
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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, ...
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How to classify ionic and covalent excited-states? [closed]
In spectroscopy it is common to describe excited-states as ionic or covalent.
I understand the concept on a toy model e.g. $\ce{H2}$ with a minimal basis set
\begin{align}
\Phi_0 &= [\chi_A(1) + \...
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What are the ways to add dynamic correlation to an MCSCF wavefunction?
We recently learned about the many types of MCSCF, which treat "static" electron correlation. There are then many ways to treat further "dynamic" electron correlation to try and ...
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What are the types of MCSCF?
Similar to:
What are the types of SCF?
What are the types of Quantum Monte Carlo?
What are the types of ab initio Molecular Dynamics?
What are the types of pseudopotentials?
What are the types of DFT?...
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Can MOLPRO (2012) calculate SA-CASSCF gradients with cc-pVDZ?
I have tried to calculate state-averaged gradients with MOLPRO using the default basis set cc-pvdz.
However, I was met with the error message:
...
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Is there a free package with robust CASSCF functionality?
Among free software packages, which one has robust CASSCF functionality? The FCI solver can be implemented in either way, e.g., direct solver, DMRG, etc.
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