A general code for fitting global potential energy surfaces via CHIPR method: Direct-Fit Diatomic and tetratomic molecules

CMR Rocha, AJC Varandas - Computer Physics Communications, 2021 - Elsevier
A general program to fit global adiabatic potential energy surfaces of up to tetratomic
molecules to ab initio points and available spectroscopic data for simple diatomics is …

A general code for fitting global potential energy surfaces via CHIPR method: Triatomic molecules

CMR Rocha, AJC Varandas - Computer Physics Communications, 2020 - Elsevier
A general program to fit global potential energy surfaces of ABC, AB 2, and A 3 triatomic
molecules to ab initio points is reported. It is based on the Combined-Hyperbolic-Inverse …

Post-complete-basis-set extrapolation of conventional and explicitly correlated coupled-cluster energies: can the convergence to the CBS limit be diagnosed?

AJC Varandas - Physical Chemistry Chemical Physics, 2021 - pubs.rsc.org
We assess benchmark correlation energies for 130 systems in test sets A24 and TS-106
both with the canonical CCSD (T) and explicitly correlated CCSD (T)-F12 methods. Aiming …

Extrapolation to the complete-basis-set limit and the implications of avoided crossings: The X Σ1g+, B Δ1g, and B′ Σ1g+ states of C2

AJC Varandas - The Journal of Chemical Physics, 2008 - pubs.aip.org
Extrapolation to the complete-basis-set limit and the implications of avoided crossings: The X
Σ1g+⁠, B Δ1g⁠, and B′ Σ1g+ states of C2 | The Journal of Chemical Physics | AIP Publishing …

Accurate CHIPR Potential Energy Surface for the Lowest Triplet State of C3

CMR Rocha, AJC Varandas - The Journal of Physical Chemistry …, 2019 - ACS Publications
We report the first global ab initio-based potential energy surface (PES) for ground-state
triplet C3 (3A′) based on accurate energies extrapolated to the complete basis set (CBS) …

Potential energy curves, partition functions and line intensities of HF and HCl molecules under the improved Hulburt‐Hirschfelder quantum mechanical anharmonic …

H Tian, Q Fan, Z Fan, J Fu, H Li, J Ma… - International Journal of …, 2022 - Wiley Online Library
Abstract An improved Hulburt‐Hirschfelder (IHH) quantum mechanical anharmonic oscillator
model which describes the exact analytical potential energy curves (PECs) of diatomic …

A new genetic algorithm to be used in the direct fit of potential energy curves to ab initio and spectroscopic data

JMC Marques, FV Prudente, FB Pereira… - Journal of Physics B …, 2008 - iopscience.iop.org
We propose a two-step genetic algorithm (GA) to fit potential energy curves to both ab initio
and spectroscopic data. In the first step, the GA is applied to fit only the ab initio points; the …

Accurate ab initio potentials at low cost via correlation scaling and extrapolation: Application to CO (AΠ1)

AJC Varandas - The Journal of chemical physics, 2007 - pubs.aip.org
A recently proposed scheme that enables high quality molecular potentials to be obtained
from small basis set calculations via scaling and extrapolation of the electron correlation to …

Accurate ab initio-based double many-body expansion potential energy surface for the adiabatic ground-state of the C3 radical including combined Jahn-Teller plus …

CMR Rocha, AJC Varandas - The Journal of Chemical Physics, 2015 - pubs.aip.org
A fully ab initio-based potential energy surface is first reported for the ground electronic state
of the C 3 radical using the double many-body expansion (DMBE) method. The DMBE form …

Accurate global ab initio potentials at low-cost by correlation scaling and extrapolation to the one-electron basis set limit

AJC Varandas - Chemical physics letters, 2007 - Elsevier
A recently proposed scheme that enables a potential energy surface corresponding to a
calculation with a large target basis set to be obtained from small basis set calculations via …