In order to extend neural network electronic structure cal-culations to larger systems, the computation complexity has to be reduced and one helpful approach is the so-called effective core potential (ECP) method (also known as pseudopotential). See Ref. [21] for a review. Electrons in each system can be divided into core electrons and valence ...Potential energy curves for the ground 1 Σ + g state of Xe 2, the first four states of the Xe + 2 ions, and the eight Xe* 2 excimer states corresponding to the addition of a 6sσ g Rydberg electron to these ion cores have been computed using averaged relativistic effective core potentials (AREP) and the self‐consistent field approximation for the …The relativistic effective core potential (RECP) or pseudopotential method is widely used in calculations on molecules containing heavy atoms 12, 13 because it reduces drastically the computational cost at the integral generation, self-consistent field (SCF) calculation and integral transformation stages.The procedure of deriving ab initio effective core potentials (ECP) to incorporate the Coulomb and exchange effects as well as orthogonality constraints from the inner core electrons is extended to include the dominant relativistic effects on the valence orbitals. An ab initio approach is then described which enables the valence electrons in heavy atoms to be treated in a standard ...2018-10-15 Update 2nd row He-core ccECPs to be consistent with JCP (2018) potentials. 2018-05-21 Added ccECPs for 2nd and 3rd row from Abdulgani Annaberdiyev (2018) and Chandler Bennett (2018). 2018-04-12 Added Trail-Needs CEPP (2015) and eCEPP (2017) potentials, basis sets, and orbitals. 2018-02-22 Add RRKJ and TM potentials for 3d …The effective core potential (ECP) approximation has been vital in electronic structure calculations for several decades. An ECP is used to replace an …Introduction. Relativistic effective core potential (RECP) methods, also called relativistic pseudopotential (PP) methods, are probably the most successful approximate methods for the various properties of molecules containing heavy atoms, since RECP calculations economically yield results that are very close to the all-electron results without introducing any empirical parameters [1, 2, 3, 4].This work integrates a powerful neural-network based model (FermiNet) with the effective core potential method, which helps to reduce the complexity of the problem by replacing inner core electrons with additional semi-local potential terms in Hamiltonian. Deep learning techniques have opened a new venue for electronic structure theory in recent years. In contrast to traditional methods, deep ...The pseudopotential must be used with a compatible basis set. Gaussian supports a new effective core potential (ECP) input format (similar to that used by ExtraBasis) which is described in the Format tab. Without any options, this keyword defaults to Pseudo=Read. However, the Cards option is by far its most-used mode.The calculations used correlationconsistent effective core potentials and corresponding VDZ basis sets for both H and C atoms from pseudopotentiallibrary.org. 74, 75 Each calculation was carried ...Jun 16, 2016 · The SDD effective core potential basis set is not suitable for the bond length calculation for PBDEs. The results of the two methods are close to the experimental data, while the all-electron basis set is more suitable for the bond length calculation for PBDEs than the SDD effective core potential basis set. The ground state geometries of small neutral Ag n (n=2-9) and cationic Ag n + (n=2-9) clusters have been determined in the framework of the Hartree-Fock and complete active space self‐consistent field (CASSCF) procedure employing a relativistic effective core potential (RECP) accounting for core-valence correlation effects (CVC). Similarities and differences between topologies of ...Dec 23, 2023 · Calculate electronic excited states using neural networks with effective core potential. The essence of atomic structure theory, quantum chemistry, and computational materials science is solving the multi-electron stationary Schrödinger equation. The Quantum Monte Carlo-based neural network wave function method has surpassed traditional post ... 8 Essential Qualities of Successful Leaders. Summary. Becoming a great leader is a journey of continuous learning and growth. It's a process — one that thrives on embracing challenges, seeking ...For geometry optimizations, the SDD basis set with effective core potential (ECP) was chosen to describe gold and iodine and 6-31G(d) basis set was employed for all other atoms. 17 This basis set combination will be referred to as BS1. Frequency calculations were carried out at the same level of theory as those for structural optimization.Introduction In recent years, the effective core-potential (ECP) method for molecular calculations has gained con- siderable attention (see reviews [1,2]). This pro- cedure allows one, in the framework of well-devel- oped nortrelativistic methods of calculation, both to reduce significantly the number of electrons under consideration and to ...We introduce new correlation consistent effective core potentials (ccECPs) for the elements I, Te, Bi, Ag, Au, Pd, Ir, Mo, and W with 4d, 5d, 6s, and 6p valence spaces. These ccECPs are given as a sum of spin-orbit averaged relativistic effective potential (AREP) and effective spin-orbit (SO) terms.8.10 Introduction to Effective Core Potentials (ECPs) The application of quantum chemical methods to elements in the lower half of the Periodic Table is more …The performance of popular Hartree–Fock-based effective core potentials in Hartree–Fock and density functional calculations of 3d transition metals has been evaluated by basis-set convergence studies for ten cases: the equilibrium bond dissociation energy (De) for dissociation of ground-state Ti2 to ground and excited atoms, the ground …@article{osti_5146072, title = {Effective core potential study of the mono- and tetracarbonyls of Ni, Pd, and Pt}, author = {Rohlfing, C M and Hay, P J}, abstractNote = {Effective core potentials (ECP's) are used to determine SCF equilibrium geometries and properties of the mono- and tetracarbonyls of nickel, palladium, and platinum. For Pd and Pt, potentials including relativistic effects are ...In our previous work we examined DFT using all-electron basis sets, but approaches incorporating effective core potentials (ECPs) are effective in reducing computational expense. With this in mind, our efforts were expanded to include evaluation of the performance of the basis set derived to approximate such an approach as well on the same set ...The idea of effective core potentials (ECPs) is based on the chemically intuitive restriction of the explicit calculations to the chemical important valence electrons, while the essentially inert atomic cores, i.e., the nucleus and the electrons in the inner shells, are replaced by a suitable parametrized (relatively simple) one-electron operator acting on the remaining valence electrons, i.e ...Diagram of a fluorine atom showing the extent of effective nuclear charge. (CC BY-SA 3.0; NikNaks via Wikipedia). The charge \(Z\) of the nucleus of a fluorine atom is 9, but the valence electrons are screened appreciably by the core electrons (four electrons from the 1s and 2s orbitals) and partially by the 7 electrons in the 2p orbitals.Interactions of eka-Hg (E112) and Hg atoms with small gold clusters were studied in the frame of the relativistic effective core potential model using the density functional theory (DFT) approach incorporating spin-dependent (magnetic) interactions.Besides, for these heavier elements the relativistic effects become important. One way to solve both problems simultaneously is to fit an effective core potential (ECP) to describe the core electrons using relativistic calculations, reducing the computational problem by treating only the valence electrons explicitly [22, 25, 27]. Most ECP ... # # Author: Qiming Sun <[email protected]> # ''' Effective core potential (ECP) This module exposes some ecp integration functions from the C implementation. Reference for ecp integral computation * Analytical integration J. Chem. Phys. 65, 3826 J. Chem. Phys. 111, 8778 J. Comput. Phys. 44, 289 * Numerical integration J. Comput. The cisplatin structure (Fig. 1) was optimized and characterized as a minimum point on the potential energy surface (PES) through harmonic frequency calculation.The calculations were performed using DFT with the hybrid GGA B3LYP functional [].The solvent effect was considered through the conductor-like polarizable continuum model (C-PCM) [], with the dielectric constant adjusted for water (ε ...Effective core potential is a type of numerical model of chemical elements so that their inner shell electrons not participate in numerical simulation. Instead, those electrons are combined with the atom core and treated as a collective potential to the remaining valence electrons. When constructedDOI: 10.1021/ct8000409 Corpus ID: 206911248; Revised Basis Sets for the LANL Effective Core Potentials. @article{Roy2008RevisedBS, title={Revised Basis Sets for the LANL Effective Core Potentials.}, author={Lindsay E. Roy and P. Jeffrey Hay and Richard L. Martin}, journal={Journal of chemical theory and computation}, year={2008}, volume={4 7}, pages={ 1029-31 }, url={https://api ...Effective core potential (ECP) integrals are amongst the most difficult one-electron integrals to calculate due to the projection operators. The radial part of these operators may include r⁰, r ...We propose large-core correlation-consistent pseudopotential basis sets for the heavy p-block elements Ga-Kr and In-Xe. The basis sets are of cc-pVTZ and cc-pVQZ quality, and have been optimized ...The calculations used correlationconsistent effective core potentials and corresponding VDZ basis sets for both H and C atoms from pseudopotentiallibrary.org. 74, 75 Each calculation was carried ...It is shown that the use of relativistic effective core potential (RECP) for heavy atoms removes the need for the empirical scaling used previously. BEB cross-sections of Ar, Kr, Xe, Cl, Br, I ...A new generation of effective core potentials: selected Lanthanides and heavy elements. We construct correlation-consistent effective core potentials (ccECPs) for a selected set of heavy atoms and f-elements that are of significant current interest in materials and chemical applications, including Y, Zr, Nb, Rh, Ta, Re, Pt, Gd, and Tb.Effective core potential basis sets. Hans Hellmann introduced pseudopotential or effective core potential in 1934, which is an approximation used to treat complex systems with simple description [76]. Pseudopotential explicitly treats only the chemically active valence electrons while the core electrons are 'frozen', being considered ...[Show full abstract] (FermiNet) with the effective core potential method, which helps to reduce the complexity of the problem by replacing inner core electrons with additional semilocal potential ...The cisplatin structure (Fig. 1) was optimized and characterized as a minimum point on the potential energy surface (PES) through harmonic frequency calculation.The calculations were performed using DFT with the hybrid GGA B3LYP functional [].The solvent effect was considered through the conductor-like polarizable continuum model (C-PCM) [], with the dielectric constant adjusted for water (ε ...The relativistic effective core potential (RECP) or pseudopotential method is widely used in calculations on molecules containing heavy atoms 12, 13 because it reduces drastically the computational cost at the integral generation, self-consistent field (SCF) calculation and integral transformation stages.Jul 7, 2015 · Effective core potential integral and gradient evaluations are accelerated via implementation on graphical processing units (GPUs). Two simple formulas are proposed to estimate the upper bounds of the integrals, and these are used for screening. A sorting strategy is designed to balance the workload between GPU threads properly. Effective core potentials model the potential directly instead. See here for a discussion of effective core potentials. Share. Cite. Improve this answer. Follow edited Jan 23, 2019 at 14:37. answered Feb 4, 2012 at 15:35. Deathbreath Deathbreath. 1,042 7 7 ...Semantic Scholar extracted view of "The ab initio Model Potential Method: A Common Strategy for Effective Core Potential and Embedded Cluster Calculations" by L. Seijo et al. Skip to search form Skip to main content Skip to account menu. Semantic Scholar's Logo. Search 216,897,579 papers from all fields of science ...Introduction. Relativistic effective core potential (RECP) methods, also called relativistic pseudopotential (PP) methods, are probably the most successful approximate methods for the various properties of molecules containing heavy atoms, since RECP calculations economically yield results that are very close to the all-electron results without introducing any empirical parameters [1, 2, 3, 4].Aug 28, 2020 · 8.10 Introduction to Effective Core Potentials (ECPs) The application of quantum chemical methods to elements in the lower half of the Periodic Table is more difficult than for the lighter atoms. There are two key reasons for this: •. the number of electrons in heavy atoms is large. •. relativistic effects in heavy atoms are often non-negligible. Gaussian Form of Effective Core Potential and Response Function Basis Set Derived from Troullier-Martins Pseudopotential: Results for Ag and Au Alkauskas, A.; Baratoff, A.; Bruder, C. Abstract. Publication: Journal of Physical Chemistry A. Pub Date: August 2004 DOI: 10.1021/jp037648t Bibcode: 2004JPCA..108.6863A ...Relativistic Effective Core Potential Method 2. The Effective Core Potential Method III 2.1. General Theory As mentioned above, the procedure is based on the conception that the chemical effects are essentially determined by the valence electrons only, the core electrons shielding the nucleus. Accordingly, the one basic8 Essential Qualities of Successful Leaders. Summary. Becoming a great leader is a journey of continuous learning and growth. It's a process — one that thrives on embracing challenges, seeking ...In DIRAC, the effective core potential (ECP) method is implemented and various subsequent correlation methods are available within the two-component or one-component effective Hamiltonian. From the inclusion (exclusion) of spin-orbit potential parameters in the input file, molecular spinors (orbitals) are obtained and this is the starting point ...For the Cl atom, we use an AREP type, correlation consistent effective core potential (ccECP) with 7 valence electrons [35]. The high accuracy of this ECP was demonstrated in the original paper ...Embedding potentials Instead of 'replacing' only an atomic core by an effective one-electron operator (ECP), the complete surrounding environment of a system (in a crystal) is 'replaced' by an effective potential: the embedding potential → see presentation given by L. Seijo D. Andrae, U Bielefeld — Bonn — 2003-07-26 41Effective core potentials (ECPs) are a useful means of replacing the core electrons in a calculation with an effective potential, thereby eliminating the need for the core basis functions, which usually require a large set of Gaussians to describe them. In addition to replacing the core, they may be used to represent relativistic effects, which ...The ground state geometries of small anionic Ag − n (n=2–9) clusters were determined in the framework of the Hartree–Fock procedure employing a relativistic effective core potential (RECP) accounting for core–valence correlation (CVC) effects. Large scale configuration interaction (CI) calculations for 5s electrons only were carried …The effective potential (also known as effective potential energy) combines multiple, perhaps opposing, effects into a single potential.In its basic form, it is the sum of the 'opposing' centrifugal potential energy with the potential energy of a dynamical system.It may be used to determine the orbits of planets (both Newtonian and relativistic) and to perform semi-classical atomic ...Ab initio effective core potentials (ECP's) have been generated to replace the Coulomb, exchange, and core‐orthogonality effects of the chemically inert core electron in the transition metal atoms Sc to Hg. For the second and third transition series relative ECP's have been generated which also incorporate the mass-velocity and Darwin relativistic effects into the potential.A consistent set of ab initio effective core potentials (ECP) has been generated for the main group elements from Na to Bi using the procedure originally developed by Kahn. The ECP’s are derived from all‐electron numerical Hartree–Fock atomic wave functions and fit to analytical representations for use in molecular calculations. For Rb to Bi the ECP’s are …Effective core potential integral and gradient evaluations are accelerated via implementation on graphical processing units (GPUs). Two simple formulas are …In DIRAC, the effective core potential (ECP) method is implemented and various subsequent correlation methods are available within the two-component or one-component effective Hamiltonian. From the inclusion (exclusion) of spin-orbit potential parameters in the input file, molecular spinors (orbitals) are obtained and this is the starting point ...A method is described for obtaining l‐dependent relativistic effective core potentials (ECPs) from Dirac–Fock self‐consistent field atomic wave functions. These potentials are designed for use in nonrelativistic (NR) valence electron Hartree–Fock calculations on atoms and molecules. The novel aspect of this approach involves the averaging of the separately …The computational investigations of lanthanide complexes using relativistic effective core potential (ECP) [60][61][62] in conjugation with density functional theory (DFT) provide accurate results ...The pseudopotential must be used with a compatible basis set. Gaussian supports a new effective core potential (ECP) input format (similar to that used by ExtraBasis) which is described in the Format tab. Without any options, this keyword defaults to Pseudo=Read. However, the Cards option is by far its most-used mode.Sadlej's electric polarization method of Gaussian basis functions was applied to the double-zeta effective core potential basis sets of Stevens, Basch, Krauss, Jasien and Cundari to generate a new augmented polarized valence double-zeta set, named as pSBKJC, which is appropriate for the calculation of dynamic polarizabilities and Raman intensities. The pSBKJC basis set was developed for the ...New Effective Core Method (Effective Core Potential and Valence Basis Set) for Al Clusters and Nanoparticles and Heteronuclear Al-Containing Molecules. …Oct 5, 2012 · We present a set of effective core potential (ECP) basis sets for rhodium atoms which are of reasonable size for use in electronic structure calculations. In these ECP basis sets, the Los Alamos ECP is used to simulate the effect of the core electrons while an optimized set of Gaussian functions, which includes polarization and diffuse ... Effective core potential is a type of numerical model of chemical elements so that their inner shell electrons not participate in numerical simulation. Instead, those electrons are combined with the atom core and treated as a collective potential to the remaining valence electrons. When constructedEffective core potential integral and gradient evaluations are accelerated via implementation on graphical processing units (GPUs). Two simple formulas are …The structure was optimized and the vibrational spectrum was calculated by DFT (B3LYP/6-31G(d)) methodology using relativistic effective core potential for U atom. The results for force constant and vibrational frequencies support the experimental assignments and the proposed model, mainly in the far-infrared region, where the metal-ligand ...The TMSZ basis set is used for gold atoms and the CEP-31G basis set is used for C, N and H atoms [30, 31], in which the effect of the core electrons is represented by effective core potential (ECP ...Effective core potential integral and gradient evaluations are accelerated via implementation on graphical processing units (GPUs). Two simple formulas are proposed to estimate the upper bounds of the integrals, and these are used for screening. A sorting strategy is designed to balance the workload …We would like to show you a description here but the site won't allow us.The present manuscript discusses the two branches of e ective core potential (ECP) approaches, i.e., the model potential (MP) and the pseudopotential (PP) tech-niques. The main focus is on those ECP schemes which proved to be successful in atomic and molecular relativistic electronic structure calculations during the pastIn this paper a complete set of effective core potentials (ECPs) and valence basis sets for the lanthanides (Ce to Lu) are derived. These ECPs are consistent not only within the lanthanide series, but also with the third-row transition metals which bracket them. A 46-electron core was chosen to provide the best compromise between computational savings and chemical accuracy. Thus, the 5s and 5p ...Jan 1, 2000 · Request PDF | On Jan 1, 2000, M. Dolg published Effective core potential | Find, read and cite all the research you need on ResearchGate You signed in with another tab or window. Reload to refresh your session. You signed out in another tab or window. Reload to refresh your session. You switched accounts on another tab or window. A recently developed compact effective core potential (ECP) scheme for lanthanides [T. R. Cundari and W. J. Stevens, J. Chem. Phys. 98, 5555 (1993)] is applied to molecular species—the lanthanide trihalides (LnX3, Ln=Ce to Lu; X=F, Cl, Br, I). This research is the first ECP study of lanthanide trihalides in which 4f electrons are explicitly included in the lanthanide valence space. The high ...In the effective core potential (ECP) approximation, 24-27 a fraction of chemically inert core electrons is replaced by the pseudopotential constructed to reproduce atomic Hartree-Fock or Dirac-Hartree-Fock results. This approach has enabled quantum chemical calculations to be carried out on molecules containing heavy atoms with highly reduced computational timings.The use of effective core potentials simplifies the identification of the core hole orbital while it has only negligible effects on the computed excitation spectrum [26]. For the calculations of absorption spectra the transition potential (TP) approximation was used [27,28] where the occupation of the N 1s core orbital at the excitation center ...The TMSZ basis set is used for gold atoms and the CEP-31G basis set is used for C, N and H atoms [30, 31], in which the effect of the core electrons is represented by effective core potential (ECP ...Low-lying potential energy curves of the IBr molecule are calculated by a combination of the equation of motion coupled cluster method and the spin–orbit multireference configuration interaction with single excitations, employing in both cases accurate relativistic effective core potentials and an extended valence basis set.ORCA can use effective core potentials (also called pseudopotentials) that can be useful for efficient calculations on molecules containing heavy elements as the chemically irrelevant core electrons are not explicitly part of the electronic problem and are replaced by a core potential function instead. Note, however, that ECPs are not the most ...Effective core potential calculations were performed by using the Los Alamos single- and double-ζ basis sets. In addition relativistic effective core potential calculations were employed.where ∈ v is a valence orbital energy and ∈ c are the core orbital energies. The c:s in the projection operators are the core orbitals, and F val is the usual Fock-operator defined in the valence space only. It is easily realized that the effect of this operator is to make the valence orbital and the core orbitals degenerate. The idea was to rotate the solutions corresponding to the core ...of these issues can be resolved with the introduction of an effective core, represented as a fixed electronic potential. This potential is typically represented as a linear combination of gaussians of varying angular momenta (M. Dolg, 2000). The introduction of an ECP results in an additional term in the core Hamiltonian, over whichWe show that the Troullier-Martins scheme for constructing scalar-relativistic pseudopotentials on a particular density functional for plane-wave calculations can be applied in Gaussian-function based LCAO codes. As an example we consider the noble metals silver and gold and derive 11-electron relativistic effective core potentials, as well as a response function basis set generated by the ...Comments on "Effective Core Potentials" [M.Dolg, Modern Methods and Algorithms of Quantum Chemistry (Ed. by J.Grotendorst, John von Neumann Institute for Computing, J\"ulich, NIC Series, Vol.1 ...
A new 11-electron relativistic effective core potential (11e-RECP) for Ag atom based on correlated level of theory and the associated atomic orbital (AO) basis set have been derived which allows for an accurate determination of excited states. This has been verified by comparing the calculated excited states of the dimer with experimental data.. Tryst website
This Letter proposes an accurate scheme using frozen core orbitals, called the frozen core potential (FCP) method, to theoretically connect model potential calculations to all-electron (AE) ones. The present scheme is based on the Huzinaga-Cantu equation combined with spin-free relativistic Douglas-Kroll-Hess Hamiltonians.Potential energy curves for the ground 1 Σ + g state of Xe 2, the first four states of the Xe + 2 ions, and the eight Xe* 2 excimer states corresponding to the addition of a 6sσ g Rydberg electron to these ion cores have been computed using averaged relativistic effective core potentials (AREP) and the self‐consistent field approximation for the …The effective potential (also known as effective potential energy) combines multiple, perhaps opposing, effects into a single potential.In its basic form, it is the sum of the 'opposing' centrifugal potential energy with the potential energy of a dynamical system.It may be used to determine the orbits of planets (both Newtonian and relativistic) and to perform semi-classical atomic ...Effective core potentials derived from these revised pseudo‐orbitals were used to compute potential energy curves for the ground states of F 2, Cl 2, and LiCl and the results are compared with previous all‐electron and effective potential calculations. Our effective potentials yield dissociation energies and bond lengths which are in ...The pseudopotential must be used with a compatible basis set. Gaussian supports a new effective core potential (ECP) input format (similar to that used by ExtraBasis) which is described in the Format tab. Without any options, this keyword defaults to Pseudo=Read. However, the Cards option is by far its most-used mode.The effective core potential (ECP) approach is one of the oldest and still one of the most frequently used methods in relativistic quantum chemistry [ 1, 2 ]. …The new method, called effective group potential, which generalizes the concept of effective core potential by including in a potential the effects of many atoms ligand, is used to calculate ...Physical Review Link ManagerEspecially the SDB-cc-pVQZ basis set in conjunction with a core polarization potential (CPP) yields excellent agreement with experiment for compounds of the later heavy p-block elements. For accurate calculations on Ga (and, to a lesser extent, Ge) compounds, explicit treatment of 13 valence electrons appears to be desirable, … calculation of effective core potential (ECP) integrals in quantum chemistry codes - GitHub - chrr/libECP: calculation of effective core potential (ECP) integrals in quantum chemistry codes The ground state geometries of small neutral Ag n (n=2-9) and cationic Ag n + (n=2-9) clusters have been determined in the framework of the Hartree-Fock and complete active space self‐consistent field (CASSCF) procedure employing a relativistic effective core potential (RECP) accounting for core-valence correlation effects (CVC). Similarities and differences between topologies of ...Effective core potentials are analyzed from the standpoint of the underlying frozen core approximation. The content of the pseudoorbital, the content of the potential, and the properties of both are elaborated, showing the points at which they differ from the frozen core approximation and where possible deficiencies might lie.The effective core potential (ECP) approach is one of the oldest and still one of the most frequently used methods in relativistic quantum chemistry [1, 2]. Following chemical intuition, an atom is partitioned into a core and a valence electron system. The chemically inert core of the atom is considered to be frozen.Request PDF | On Jan 1, 2000, M. Dolg published Effective core potential | Find, read and cite all the research you need on ResearchGate@misc{li2021fermionic, title={Fermionic Neural Network with Effective Core Potential}, author={Xiang Li and Cunwei Fan and Weiluo Ren and Ji Chen}, year={2021}, eprint={2108.11661}, archivePrefix={arXiv}, primaryClass={physics.chem-ph} } About. An implementation combining FermiNet with effective core potential (ecp). ...I was trying to perform a geometry optimization for a palladium complex taking into account the effective core potential for Pd by using the EMSL basis set exchange web page ECP specifications but ...Aug 2, 2022 · We introduce new correlation consistent effective core potentials (ccECPs) for the elements I, Te, Bi, Ag, Au, Pd, Ir, Mo, and W with 4 d, 5 d, 6 s, and 6 p valence spaces. These ccECPs are given as a sum of spin-orbit averaged relativistic effective potential (AREP) and effective spin–orbit (SO) terms. The effective core potential (ECP) approach is one of the oldest and still one of the most frequently used methods in relativistic quantum chemistry [1, 2]. Following chemical intuition, an atom is partitioned into a core and a valence electron system. The chemically inert core of the atom is considered to be frozen.The performance of popular Hartree-Fock-based effective core potentials in Hartree-Fock and density functional calculations of 3d transition metals has been evaluated by basis-set convergence studies for ten cases: the equilibrium bond dissociation energy (De) for dissociation of ground-state Ti2 to ground and excited atoms, the ground-state dissociation energies of FeO, Cu2, ScH, TiH, Sc2 ....