Calculations Of Molecular Electric Properties Research Articles

Augmented Gaussian basis sets for the elements K, Sc–Kr, Rb, and Y–Xe: Application in HF, MP2, and DFT calculations of molecular electric properties

Augmented Gaussian basis sets of triple and quadruple zeta valence qualities plus polarization functions for the atoms K, from Sc to Kr, Rb, and from Y to Xe are presented. They were constructed from the all-electron unaugmented sets by addition of diffuse functions (s, p, d, f, g, and h symmetries) that were optimized for the anion ground states. From these sets, Hartree–Fock, second-order Mϕller–Plesset perturbation theory, and density functional theory electric dipole moment and polarizabilities for a sample of molecules as well as for Cun and Agn (n⩽4) clusters were calculated and compared with theoretical and experimental values available in the literature.

Augmented Gaussian basis set of double zeta valence quality for the atoms Rb and Y–Xe: Application in DFT calculations of molecular electric properties

Augmented Gaussian basis set of double zeta valence quality plus polarization functions for the atoms Rb and from Y to Xe is presented. It was generated from the all-electron unaugmented set by addition of diffuse functions (s, p, d, and f symmetries) that were optimized for the anion ground states. From this set, density functional theory electric dipole moment and dipole polarizability for a sample of molecules were calculated and compared with theoretical and experimental values available in the literature. Our results give good agreement with experimental and benchmark values.

Augmented Gaussian basis sets of double and triple zeta valence qualities for the atoms K and Sc–Kr: Applications in HF, MP2, and DFT calculations of molecular electric properties

Augmented Gaussian basis sets of double and triple zeta valence qualities plus polarization functions for the atoms K and from Sc to Kr are presented. They were generated from the all-electron unaugmented sets by addition of diffuse functions (s, p, d, f, and g symmetries) that were optimized for the anion ground states. From these sets, Hartree–Fock, second-order Møller–Plesset perturbation theory, and density functional theory electric dipole moment and dipole polarizability calculations for a sample of molecules were carried out. Comparison with theoretical and experimental values available in the literature was done.

Augmented Gaussian basis set of quintuple zeta valence quality for H and from Li to Ar: Applications in DFT calculations of molecular electric properties

Augmented Gaussian basis set of quintuple zeta valence quality plus polarization functions (A5ZP) for H and Li–Ar is presented. It was determined from the 5ZP basis set by addition of diffuse (s and p symmetries) and polarization (p, d, f, g, and h symmetries) functions that were optimized for the anion at the Hartree–Fock and Mϕller–Plesset second-order levels, respectively. It was shown that in general this basis set in combination with the density functional theory can be used with success to predict electric properties for a sample of molecules. Comparison with theoretical and experimental values available in the literature is done.

Reduced-size polarized basis sets for calculations of molecular electric properties. IV. First-row transition metals

Recent studies of the perturbation-dependent basis sets have indicated the possibility of a significant reduction of the size of the usual CGTO sets without considerable loss of accuracy in calculations of molecular electric properties. The resulting (ZPolX) basis sets have been developed for several atoms of the first and second row of the Periodic Table. The same method of the ZPolX basis set generation is extended for the first-row transition metals and the corresponding contracted ZPolX basis sets of the size [6s5p3d1f] are determined for both nonrelativistic and scalar relativistic calculations. The performance of the ZPolX basis sets is verified in calculations on the first-row transition metal oxides at the level of the ROHF, ROHF/CASPT2, and ROHF/CCSD(T) approximations. Also the study of the dipole polarizability of TiCl4 confirms the excellent features of these very compact basis sets. The ZPolX basis sets for nonrelativistic and relativistic calculations of molecular electric properties are available on the web page http://www.chem.uni.torun.pl/zchk/basis-sets.html.

Reduced–size polarized basis sets for calculations of molecular electric properties. III. Second–row atoms

Reduced–size polarized (ZmPolX) basis sets are developed for the second–row atoms X = Si, P, S, and Cl. The generation of these basis sets follows from a simple physical model of the polarization effect of the external electric field which leads to highly compact polarization functions to be added to the chosen initial basis set. The performance of the ZmPolX sets has been investigated in calculations of molecular dipole moments and polarizabilities. Only a small deterioration of the quality of the calculated molecular electric properties has been found. Simultaneously the size of the present reduced–size ZmPolX basis sets is about one-third smaller than that of the usual polarized (PolX) sets. This reduction considerably widens the range of applications of the ZmPolX sets in calculations of molecular dipole moments, dipole polarizabilities, and related properties.

Reduced‐size polarized basis sets for calculations of molecular electric properties. I. The basis set generation

Following the recent studies of basis sets explicitly dependent on oscillatory external electric field we have investigated the possibility of some further truncation of the so-called polarized basis sets without any major deterioration of the computed data for molecular dipole moments, dipole polarizabilities, and related electric properties of molecules. It has been found that basis sets of contracted Gaussian functions of the form [3s1p] for H and [4s3p1d] for the first-row atoms can satisfy this requirement with particular choice of contractions in their polarization part. With m denoting the number of primitive GTOs in the contracted polarization function, the basis sets devised in this article will be referred to as the ZmPol sets. In comparison with earlier, medium-size polarized basis sets (PolX), these new ZmPol basis sets are reduced by 2/3 in their size and lead to the order of magnitude computing time savings for large molecules. Simultaneously, the dipole moment and polarizability data remain at almost the same level of accuracy as in the case of the PolX sets. Among a variety of possible applications in computational chemistry, the ZmPolX are also to be used for calculations of frequencies and intensities in the Raman spectra of large organic molecules (see Part II, this issue).

Reduced‐size polarized basis sets for calculations of molecular electric properties. II. Simulation of the Raman spectra

The accuracies of the calculated vibrational frequencies and Raman intensities given by two new, highly compact Pol-type basis sets, Z2PolX and Z3PolX, have been determined and compared to the 6-31G(d), PolX, and aug-cc-pVTZ basis sets. Calculation of accurate Raman intensities has previously required large basis sets, but the ZmPolX basis sets are smaller even than PolX, which are the most compact basis sets able to calculate accurate Raman intensities. For the largest compound studied, C5H10O2, Z3PolX required more than an order of magnitude less CPU time than PolX, which has been shown to be 10 times faster than aug-cc-pVTZ. Two sets of test molecules were studied: one was a series of small molecules for which experimental values for absolute Raman activities were available; the second was a series of medium-sized molecules (mainly common organic solvents) where only relative Raman band intensities were available. The accuracies of the Raman intensities given by both of the ZmPolX basis sets were good compared to those of the PolX and aug-cc-pVTZ sets, and much better than the 6-31G(d) values. The errors in even unscaled frequency values <2000 cm(-1) were also acceptable and were slightly lower for Z3PolX than Z2PolX (30 cm(-1) vs. 48 cm(-1)). The combination of good intensity and frequency data meant that for the medium-sized organic molecules there was a close correspondence between the simulated Raman spectra and experimental data, and that the observed bands could easily be assigned on the basis of these calculations. Achieving this level of accuracy in the simulations at modest computational cost should now allow computational methods to be combined with experimental Raman studies much more widely than is currently the case.

Density functional calculations of molecular electric properties in iron containing systems

Calculations of dipole moments, static mean polarizabilities and mean first hyperpolarizabilities of iron containing systems calculated in the framework of density functional theory are presented. The calculations were of all-electron type and performed using a finite field approach implemented in the density functional program A llC hem. A newly developed first-order field induced iron basis set for density functional calculation was employed. The calculated properties are in good agreement with the data available in the literature. This work shows that the employed iron basis set can be used to compute reliable molecular electric properties of iron containing compounds.

Standardized Medium-Size Basis Sets for Calculations of Molecular Electric Properties: Group IIIA

The idea of what is called the basis set polarization method is reviewed and the available polarized basis sets are surveyed. Following the basis set polarization approach and certain empirical rules developed earlier, the first-order polarized basis sets for the Group IIIA elements are generated. These basis sets have been developed for both nonrelativistic and spin-averaged Douglas-Kroll relativistic calculations. Their performance is tested in calculations of atomic dipole polarizabilities and in high-level-correlated calculations of the dipole moments of GaF, InF, and TlF. The relativistic effects have been found to significantly affect the calculated molecular dipole moments of the studied fluorides. The results are in satisfactory agreement with reference data. The present study completes the library of the first-order polarized basis sets for all atoms of the main groups of the Periodic Table.

A basis set study of coupled cluster and full configuration interaction calculations of molecular electric properties for BH

Static and frequency-dependent polarizabilities and first and second hyperpolarizabilities have been calculated for BH using full configuration interaction (FCI) and the hierarchy of coupled cluster models CCS, CC2 and CCSD. A systematic basis set investigation has been performed and has been used to estimate basis set limit results. The FCI results are used to calibrate the accuracy of the coupled cluster model hierarchy. No systematic improvements are found in CC2 relative to CCS. The CCSD model appears to be robust and represents a significant improvement relative to CCS and CC2. The CCSD results are in close agreement with the FCI results for α and γ, while for β a similar accuracy requires considerations of a higher level in the coupled cluster hierarchy.

Standardized basis sets for high-level-correlated relativistic calculations of atomic and molecular electric properties in the spin-averaged Douglas-Kroll approximation

The technique previously developed for the generation of the so-called first-order polarized basis sets for accurate non-relativistic calculations of molecular electric properties is used to obtain similar basis sets suitable for calculations in the Douglas-Kroll no-pair approximation. The corresponding (relativistic) basis sets are constructed for atoms of groups Ia and IIa of the Periodic Table and tested in calculations of atomic and ionic polarizabilities. Also the first ionization potential of the group Ia and the first and second ionization potential of the group IIa metals have been evaluated to provide additional qualification of the generated basis sets. The present results are compared with earlier non-relativistic and quasirelativistic data and the role of the relativistic effect is discussed.

Polarized basis sets for high-level-correlated calculations of molecular electric properties

Polarized basis sets for high-level-correlated calculations of molecular electric properties

Polarized basis sets for high-level-correlated calculations of molecular electric properties

Polarized basis sets for high-level-correlated calculations of molecular electric properties

Polarized basis sets for high-level-correlated calculations of molecular electric properties

The first-order polarized basis sets are generated for Zn, Cd, and Hg and their performance is tested in high-level-correlated calculations of electric dipole polarizabilities of these atoms. The present results calculated at the level of the non-relativistic CCSD(T) approximation with 12 explicitly correlated electrons are: 40.4 a.u. for Zn, 56.3 a.u. for Cd, and 58.0 a.u. for Hg. Upon including the relativistic and electron correlation-relativistic corrections within the quasirelativistic scheme based on the mass-velocity and Darwin terms these values are reduced to 37.9 a.u., 47.6 and 31.8 a.u., respectively. The derived polarized basis sets have been also used for the evaluation of the dipole polarizability of singly and doubly positive ions of the group IIb elements and are recommended for calculations of interaction energies and interaction-induced electric properties in both neutral and charged systems.

Polarized basis sets for high-level-correlated calculations of molecular electric properties

Polarized basis sets for high-level-correlated calculations of molecular electric properties

Determination of physically justified STO basis sets for molecular dipole moment and polarizability calculations

Two alternative methods of physically justified adaptation of the initial STO basis set have been suggested for ab initio calculations of molecular electric properties. These have been based either on consideration of the basis set dependence on the external electric field strength or on its extension. Dipole moment and polarizability test calculations of tenelectron hydride molecules have demonstrated the effectiveness and economy of the approaches suggested.

Determination of physically justified STO basis sets for molecular dipole moment and polarizability calculations

Two alternative methods of physically justified adaptation of the initial STO basis set have been suggested for ab initio calculations of molecular electric properties. These have been based either on consideration of the basis set dependence on the external electric field strength or on its extension. Dipole moment and polarizability test calculations of tenelectron hydride molecules have demonstrated the effectiveness and economy of the approaches suggested.

Electron-correlation and relativistic contributions to atomic dipole polarizabilities: Alkali-metal atoms.

Electric-dipole polarizabilities of K, Rb, Cs, and Fr are calculated in the framework of the quasirelativistic method based on mass-velocity and Darwin terms in the Pauli Hamiltonian. The electron-correlation contribution due to atomic cores is taken into account at two levels of approximation. The next-to-valence-shell contributions follow from the appropriate complete active-space multiconfiguration self-consistent-field calculations while the remaining core correlation effects are evaluated by using a second-order-perturbation method. Both pure relativistic and mixed correlation-relativistic contributions are evaluated. The present nonrelativistic results for K (44.6 A${\mathrm{\r{}}}^{3}$), Rb (60.8 A${\mathrm{\r{}}}^{3}$), Cs (72.8 A${\mathrm{\r{}}}^{3}$), and Fr (81.8 A${\mathrm{\r{}}}^{3}$) are reduced by 0.8 A${\mathrm{\r{}}}^{3}$, 11.3 A${\mathrm{\r{}}}^{3}$, 11.5 A${\mathrm{\r{}}}^{3}$, and 33.5 A${\mathrm{\r{}}}^{3}$, respectively, due to relativistic and correlation-relativistic corrections. The quasirelativistic results for K, Rb, and Cs are in good agreement with experimental data. The predicted dipole polarizability of Fr is 48.3 A${\mathrm{\r{}}}^{3}$. Additionally, polarized basis sets for Cs and Fr for calculations of molecular electric properties have been generated in this study.

Medium-size polarized basis sets for high-level-correlated calculations of molecular electric properties

The first-order polarized basis sets for the use in high-level-correlated investigations of molecular electric properties have been generated for Pb, Bi, Po, and At. The performance of the standard [10.17.14.5/13.11.8.2] and extended [20.17.14.9/13.11.8.4] basis sets has been examined in nonrelativistic and quasirelativistic calculations for atoms and simple closed-shell hydrides. The relativistic contributions to electric dipole properties of those systems have been evaluated by using the recently developed quasirelativistic scheme