Communication: On the isotope anomaly of nuclear quadrupole coupling in molecules

Filatov, Michael; Zou, Wenli; Cremer, Dieter

doi:10.1063/1.4757568

Cited by 17 publications

(20 citation statements)

References 35 publications

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“…,

\frac{ν_{Q} (I_{1})}{ν_{Q} (I_{2})} = \frac{Q_{I_{1}}}{Q_{I_{2}}} (1 + \frac{1}{〈 {scriptV}_{c c} 〉} \frac{\partial 〈 {scriptV}_{c c} 〉}{\partial R} |_{R = R_{I_{2}}} Δ R_{12}) + O (Δ R_{12}^{2})

where

R_{I_{2}}

is the charge radius of the isotope I 2 and

Δ R_{12}

is the variation of the charge radius between isotopes I 1 and I 2 . Calculating the logarithmic derivative of the principal EFG value in a series of gold compounds, FZC found that the nuclear quadrupole anomaly

^{195} Δ_{Au}^{197}

can reach values up to 0.2% according to NESC/CCSD calculations. An anomaly of such a magnitude should be reflected by measured NQCC, as the accuracy of current techniques in microwave spectroscopy is sufficient to detect an anomaly predicted for the

_{79}^{195} Au

_{79}^{197} Au

pair of isotopes …”

Section: Nesc Analytic Energy Derivativesmentioning

confidence: 99%

Calculation of response properties with the normalized elimination of the small component method

Filatov

Zou

Cremer

2013

Int J of Quantum Chemistry

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The normalized elimination of the small component method is a first principles two-component relativistic approach that leads to the Dirac-exact description of one-electron systems. Therefore, it is an ideal starting point for developing procedures, by which first-and second-order response properties can be routinely calculated. We present algorithms and methods for the calculation of molecular response properties such as geometries, dipole moments, hyperfine structure constants, vibrational frequencies and force constants, electric polarizabilities, infrared intensities and so forth. The described formalisms are applied to molecules containing mercury and other heavy elements, which require a relativistic treatment. Perspectives for the future development and application of Dirac-exact methods are outlined.

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“…,

\frac{ν_{Q} (I_{1})}{ν_{Q} (I_{2})} = \frac{Q_{I_{1}}}{Q_{I_{2}}} (1 + \frac{1}{〈 {scriptV}_{c c} 〉} \frac{\partial 〈 {scriptV}_{c c} 〉}{\partial R} |_{R = R_{I_{2}}} Δ R_{12}) + O (Δ R_{12}^{2})

where

R_{I_{2}}

is the charge radius of the isotope I 2 and

Δ R_{12}

^{195} Δ_{Au}^{197}

_{79}^{195} Au

_{79}^{197} Au

pair of isotopes …”

Section: Nesc Analytic Energy Derivativesmentioning

confidence: 99%

Calculation of response properties with the normalized elimination of the small component method

Filatov

Zou

Cremer

2013

Int J of Quantum Chemistry

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“…Analytic second derivatives have also been explored in the computation of nuclear Hessians as well as NMR chemical shieldings . Initial applications of SFX2C‐1e energy derivatives in the calculation of the properties of heavy‐element compounds have turned out promising . A more detailed discussion of analytic SFX2C‐1e energy derivatives is presented in the following.…”

Section: State‐of‐the‐art Analytic Derivative Theory In Relativistic mentioning

confidence: 99%

Analytic energy derivatives in relativistic quantum chemistry

Cheng

Stopkowicz

Gauß

2014

Int J of Quantum Chemistry

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In this review, we discuss the current status of analytic derivative theory in relativistic quantum chemistry. A brief overview of the basic theory for the available relativistic quantum chemical methods as well as the state-of-the-art development of their analytic energy derivatives is given. Among the various relativistic quantum chemical methods, cost-effective approaches based on spin separation and/or on the matrix representation of two-component theory have been proven particularly promising for the accurate and efficient treatment of relativistic effects in electron correlation calculations. We highlight analytic derivative techniques for these cost-effective relativistic quantum chemical approaches including direct perturbation theory, the spin-free Dirac-Coulomb approach, and the exact two-component theory in its one-electron variant. An outlook is given on future developments of analytic energy derivative techniques for relativistic quantum chemical methods, again with an emphasis on cost-effective schemes.

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“…8 As for the calculation of second order response properties, we developed the methodology for the analytic calculation of vibrational frequencies, 3,9 static electric polarizabilities, or infrared intensities 3 utilizing the 1c-NESC method. We applied these methods to predict molecular properties of mercury, 10 gold, 11 uranium containing molecules, 3 or other relativistic molecules. 12 In view of the importance of spin-orbit coupling (SOC) for atomic and molecular properties, [13][14][15][16][17][18][19][20][21] we extended, in another project, the 1c-NESC approach to a 2c-NESC method that reliably predicts the effects of SOC on the relative energies of relativistic systems.…”

Section: Introductionmentioning

confidence: 99%

Analytical energy gradient for the two-component normalized elimination of the small component method

Zou

Filatov

Cremer

2015

The Journal of Chemical Physics

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The analytical gradient for the two-component Normalized Elimination of the Small Component (2c-NESC) method is presented. The 2c-NESC is a Dirac-exact method that employs the exact two-component one-electron Hamiltonian and thus leads to exact Dirac spin-orbit (SO) splittings for one-electron atoms. For many-electron atoms and molecules, the effect of the two-electron SO interaction is modeled by a screened nucleus potential using effective nuclear charges as proposed by Boettger [Phys. Rev. B 62, 7809 (2000)]. The effect of spin-orbit coupling (SOC) on molecular geometries is analyzed utilizing the properties of the frontier orbitals and calculated SO couplings. It is shown that bond lengths can either be lengthened or shortened under the impact of SOC where in the first case the influence of low lying excited states with occupied antibonding orbitals plays a role and in the second case the jj-coupling between occupied antibonding and unoccupied bonding orbitals dominates. In general, the effect of SOC on bond lengths is relatively small (≤5% of the scalar relativistic changes in the bond length). However, large effects are found for van der Waals complexes Hg2 and Cn2, which are due to the admixture of more bonding character to the highest occupied spinors.

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Communication: On the isotope anomaly of nuclear quadrupole coupling in molecules

Cited by 17 publications

References 35 publications

Calculation of response properties with the normalized elimination of the small component method

Calculation of response properties with the normalized elimination of the small component method

Analytic energy derivatives in relativistic quantum chemistry

Analytical energy gradient for the two-component normalized elimination of the small component method

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