Martin Schütz - Academia.edu (original) (raw)
Papers by Martin Schütz
Angewandte Chemie International Edition, 2006
With the advent of combined quantum mechanics / molecular mechanics (QM/MM) methods, enzymatic re... more With the advent of combined quantum mechanics / molecular mechanics (QM/MM) methods, enzymatic reactions have become accessible to theoretical modeling in recent years. QM/MM calculations on enzymes have generally been restricted to semiempirical or density functional QM treatments, which are realistic but of limited accuracy and cannot be improved in a systematic manner. In this work it has for the first time been possible to apply high-level coupled-cluster ab initio electronic structure methods to enzymatic catalysis, in a QM/MM framework. Excellent agreement is obtained between the computed and the experimentally determined activation barriers for two quite different enzymatic reactions, a Claisen rearrangement in chorismate mutase and an electrophilic aromatic substitution in parahydroxybenzoate hydroxylase. This agreement between experimental and converged theoretical results has broader implications concerning the role of specific dynamic effects in enzyme catalysis that are currently under debate: at least for the two enzymes studied here, such dynamic effects must be small since standard transition state theory describes the reactivity quantitatively.
Berichte der Bunsengesellschaft für physikalische Chemie, 1995
Physical Chemistry Chemical Physics, 2011
The electronic structure of the zero-gap two-dimensional graphene has a charge neutrality point e... more The electronic structure of the zero-gap two-dimensional graphene has a charge neutrality point exactly at the Fermi level that limits the practical application of this material. There are several ways to modify the Fermi-level-region of graphene, e.g. adsorption of graphene on different substrates or different molecules on its surface. In all cases the so-called dispersion or van der Waals interactions
The Journal of Chemical Physics, 2015
We describe theory and implementation of oscillator strengths, orbital-relaxed first-order proper... more We describe theory and implementation of oscillator strengths, orbital-relaxed first-order properties, and nuclear gradients for the local algebraic diagrammatic construction scheme through second order. The formalism is derived via time-dependent linear response theory based on a second-order unitary coupled cluster model. The implementation presented here is a modification of our previously developed algorithms for Laplace transform based local time-dependent coupled cluster linear response (CC2LR); the local approximations thus are state specific and adaptive. The symmetry of the Jacobian leads to considerable simplifications relative to the local CC2LR method; as a result, a gradient evaluation is about four times less expensive. Test calculations show that in geometry optimizations, usually very similar geometries are obtained as with the local CC2LR method (provided that a second-order method is applicable). As an exemplary application, we performed geometry optimizations on the low-lying singlet states of chlorophyllide a.
The Journal of Chemical Physics, 2015
We introduce orbital specific virtuals (OSVs) to represent the truncated pair-specific virtual sp... more We introduce orbital specific virtuals (OSVs) to represent the truncated pair-specific virtual space in periodic local Møller-Plesset perturbation theory of second order (LMP2). The OSVs are constructed by diagonalization of the LMP2 amplitude matrices which correspond to diagonal Wannier-function (WF) pairs. Only a subset of these OSVs is adopted for the subsequent OSV-LMP2 calculation, namely, those with largest contribution to the diagonal pair correlation energy and with the accumulated value of these contributions reaching a certain accuracy. The virtual space for a general (non diagonal) pair is spanned by the union of the two OSV sets related to the individual WFs of the pair. In the periodic LMP2 method, the diagonal LMP2 amplitude matrices needed for the construction of the OSVs are calculated in the basis of projected atomic orbitals (PAOs), employing very large PAO domains. It turns out that the OSVs are excellent to describe short range correlation, yet less appropriate for long range van der Waals correlation. In order to compensate for this bias towards short range correlation, we augment the virtual space spanned by the OSVs by the most diffuse PAOs of the corresponding minimal PAO domain. The Fock and overlap matrices in OSV basis are constructed in the reciprocal space. The 4-index electron repulsion integrals are calculated by local density fitting and, for distant pairs, via multipole approximation. New procedures for determining the fit-domains and the distant-pair lists, leading to higher efficiency in the 4-index integral evaluation, have been implemented. Generally, and in contrast to our previous PAO based periodic LMP2 method, the OSV-LMP2 method does not require anymore great care in the specification of the individual domains (to get a balanced description when calculating energy differences) and is in that sense a black box procedure. Discontinuities in potential energy surfaces, which may occur for PAO-based calculations if one is not careful, virtually disappear for OSV-LMP2. Moreover, due to much increased compactness of the pair-specific virtual spaces, the OSV-LMP2 calculations are faster and require much less memory than PAO-LMP2 calculations, despite the noticeable overhead of the initial OSV construction procedure.
Physical Review B, 2014
In this work we employ ab initio electronic structure theory at a very high level to resolve a lo... more In this work we employ ab initio electronic structure theory at a very high level to resolve a long standing experimental controversy; the interaction between helium and the MgO (100) surface has been studied extensively by other groups, employing diverse experimental approaches. Nevertheless, the binding energy of the lowest bound state is still unclear: the existence of a state at around −5.5 meV is well established but a state at −10 meV has also been reported. The MgO (100)-He system captures the fundamental physics involved in many adsorption problems; the weak binding is governed by long-range electronic correlation for which a fully predictive theory applicable to the solid state has been elusive. The above-mentioned experimental controversy can now be resolved on the basis of the calculations presented in this work. We performed three-dimensional vibrational dynamics calculations on a highly accurate potential-energy surface. The latter was constructed using a method which systematically approaches the exact limit in its treatment of electronic correlation. The outcome is clear: our calculations do not support the existence of a bound state around −10 meV.
The Journal of chemical physics, Jan 14, 2014
In this paper, we present theory and implementation of an efficient program for calculating magne... more In this paper, we present theory and implementation of an efficient program for calculating magnetizabilities and rotational g tensors of closed-shell molecules at the level of local second-order Møller-Plesset perturbation theory (MP2) using London orbitals. Density fitting is employed to factorize the electron repulsion integrals with ordinary Gaussians as fitting functions. The presented program for the calculation of magnetizabilities and rotational g tensors is based on a previous implementation of NMR shielding tensors reported by S. Loibl and M. Schütz [J. Chem. Phys. 137, 084107 (2012)]. Extensive test calculations show (i) that the errors introduced by density fitting are negligible, and (ii) that the errors of the local approximation are still rather small, although larger than for nuclear magnetic resonance (NMR) shielding tensors. Electron correlation effects for magnetizabilities are tiny for most of the molecules considered here. MP2 appears to overestimate the correla...
Linear-Scaling Techniques in Computational Chemistry and Physics, 2011
Local methods for the description of electron correlation in ground and electronically excited st... more Local methods for the description of electron correlation in ground and electronically excited states of molecules, as implemented in the MOLPRO system of ab initio programs, are reviewed. Recent improvements in the performance of the local method resulting from an implementation of the density-fitting technique for all electron-repulsion integrals are discussed. Local fitting approximations lead to linear scaling of CPU
Physical chemistry chemical physics : PCCP, Jan 21, 2014
In this work we simulate the diffraction peak intensities of He beams scattered on the MgO(100) s... more In this work we simulate the diffraction peak intensities of He beams scattered on the MgO(100) surface from first principles. It turns out that diffraction peak intensities are extremely sensitive to the quality of the potential describing the He-MgO surface interaction. Achieving the required accuracy in first principles calculations is very challenging indeed. The present work describes a first principles protocol able to achieve very high accuracy for reasonable computational cost. This method is based on periodic local second-order Møller-Plesset perturbation theory where systematic corrections for basis set truncation and for high-order electronic correlation are introduced using coupled cluster calculations on finite model systems mimicking the target system. For the He-MgO system the requirements with respect to the level of theory are very high; it turns out that contributions from connected quadruple excitations are non-negligible. Here we demonstrate that using this proto...
Journal of Molecular Structure: THEOCHEM, 1992
... Theochem), 276 (1992) 117-132 117 Elsevier Science Publishers BV, Amsterdam Structures and vi... more ... Theochem), 276 (1992) 117-132 117 Elsevier Science Publishers BV, Amsterdam Structures and vibrations of phenol "HgO and d-phenoI'DgO based on ab initio calculations Martin Schiitz, Thomas Burgi and Samuel Leutwyler Institut fur ... 26 CW Bock and M. Trachtman, J. Mol. ...
Angewandte Chemie International Edition, 2006
With the advent of combined quantum mechanics / molecular mechanics (QM/MM) methods, enzymatic re... more With the advent of combined quantum mechanics / molecular mechanics (QM/MM) methods, enzymatic reactions have become accessible to theoretical modeling in recent years. QM/MM calculations on enzymes have generally been restricted to semiempirical or density functional QM treatments, which are realistic but of limited accuracy and cannot be improved in a systematic manner. In this work it has for the first time been possible to apply high-level coupled-cluster ab initio electronic structure methods to enzymatic catalysis, in a QM/MM framework. Excellent agreement is obtained between the computed and the experimentally determined activation barriers for two quite different enzymatic reactions, a Claisen rearrangement in chorismate mutase and an electrophilic aromatic substitution in parahydroxybenzoate hydroxylase. This agreement between experimental and converged theoretical results has broader implications concerning the role of specific dynamic effects in enzyme catalysis that are currently under debate: at least for the two enzymes studied here, such dynamic effects must be small since standard transition state theory describes the reactivity quantitatively.
Berichte der Bunsengesellschaft für physikalische Chemie, 1995
Physical Chemistry Chemical Physics, 2011
The electronic structure of the zero-gap two-dimensional graphene has a charge neutrality point e... more The electronic structure of the zero-gap two-dimensional graphene has a charge neutrality point exactly at the Fermi level that limits the practical application of this material. There are several ways to modify the Fermi-level-region of graphene, e.g. adsorption of graphene on different substrates or different molecules on its surface. In all cases the so-called dispersion or van der Waals interactions
The Journal of Chemical Physics, 2015
We describe theory and implementation of oscillator strengths, orbital-relaxed first-order proper... more We describe theory and implementation of oscillator strengths, orbital-relaxed first-order properties, and nuclear gradients for the local algebraic diagrammatic construction scheme through second order. The formalism is derived via time-dependent linear response theory based on a second-order unitary coupled cluster model. The implementation presented here is a modification of our previously developed algorithms for Laplace transform based local time-dependent coupled cluster linear response (CC2LR); the local approximations thus are state specific and adaptive. The symmetry of the Jacobian leads to considerable simplifications relative to the local CC2LR method; as a result, a gradient evaluation is about four times less expensive. Test calculations show that in geometry optimizations, usually very similar geometries are obtained as with the local CC2LR method (provided that a second-order method is applicable). As an exemplary application, we performed geometry optimizations on the low-lying singlet states of chlorophyllide a.
The Journal of Chemical Physics, 2015
We introduce orbital specific virtuals (OSVs) to represent the truncated pair-specific virtual sp... more We introduce orbital specific virtuals (OSVs) to represent the truncated pair-specific virtual space in periodic local Møller-Plesset perturbation theory of second order (LMP2). The OSVs are constructed by diagonalization of the LMP2 amplitude matrices which correspond to diagonal Wannier-function (WF) pairs. Only a subset of these OSVs is adopted for the subsequent OSV-LMP2 calculation, namely, those with largest contribution to the diagonal pair correlation energy and with the accumulated value of these contributions reaching a certain accuracy. The virtual space for a general (non diagonal) pair is spanned by the union of the two OSV sets related to the individual WFs of the pair. In the periodic LMP2 method, the diagonal LMP2 amplitude matrices needed for the construction of the OSVs are calculated in the basis of projected atomic orbitals (PAOs), employing very large PAO domains. It turns out that the OSVs are excellent to describe short range correlation, yet less appropriate for long range van der Waals correlation. In order to compensate for this bias towards short range correlation, we augment the virtual space spanned by the OSVs by the most diffuse PAOs of the corresponding minimal PAO domain. The Fock and overlap matrices in OSV basis are constructed in the reciprocal space. The 4-index electron repulsion integrals are calculated by local density fitting and, for distant pairs, via multipole approximation. New procedures for determining the fit-domains and the distant-pair lists, leading to higher efficiency in the 4-index integral evaluation, have been implemented. Generally, and in contrast to our previous PAO based periodic LMP2 method, the OSV-LMP2 method does not require anymore great care in the specification of the individual domains (to get a balanced description when calculating energy differences) and is in that sense a black box procedure. Discontinuities in potential energy surfaces, which may occur for PAO-based calculations if one is not careful, virtually disappear for OSV-LMP2. Moreover, due to much increased compactness of the pair-specific virtual spaces, the OSV-LMP2 calculations are faster and require much less memory than PAO-LMP2 calculations, despite the noticeable overhead of the initial OSV construction procedure.
Physical Review B, 2014
In this work we employ ab initio electronic structure theory at a very high level to resolve a lo... more In this work we employ ab initio electronic structure theory at a very high level to resolve a long standing experimental controversy; the interaction between helium and the MgO (100) surface has been studied extensively by other groups, employing diverse experimental approaches. Nevertheless, the binding energy of the lowest bound state is still unclear: the existence of a state at around −5.5 meV is well established but a state at −10 meV has also been reported. The MgO (100)-He system captures the fundamental physics involved in many adsorption problems; the weak binding is governed by long-range electronic correlation for which a fully predictive theory applicable to the solid state has been elusive. The above-mentioned experimental controversy can now be resolved on the basis of the calculations presented in this work. We performed three-dimensional vibrational dynamics calculations on a highly accurate potential-energy surface. The latter was constructed using a method which systematically approaches the exact limit in its treatment of electronic correlation. The outcome is clear: our calculations do not support the existence of a bound state around −10 meV.
The Journal of chemical physics, Jan 14, 2014
In this paper, we present theory and implementation of an efficient program for calculating magne... more In this paper, we present theory and implementation of an efficient program for calculating magnetizabilities and rotational g tensors of closed-shell molecules at the level of local second-order Møller-Plesset perturbation theory (MP2) using London orbitals. Density fitting is employed to factorize the electron repulsion integrals with ordinary Gaussians as fitting functions. The presented program for the calculation of magnetizabilities and rotational g tensors is based on a previous implementation of NMR shielding tensors reported by S. Loibl and M. Schütz [J. Chem. Phys. 137, 084107 (2012)]. Extensive test calculations show (i) that the errors introduced by density fitting are negligible, and (ii) that the errors of the local approximation are still rather small, although larger than for nuclear magnetic resonance (NMR) shielding tensors. Electron correlation effects for magnetizabilities are tiny for most of the molecules considered here. MP2 appears to overestimate the correla...
Linear-Scaling Techniques in Computational Chemistry and Physics, 2011
Local methods for the description of electron correlation in ground and electronically excited st... more Local methods for the description of electron correlation in ground and electronically excited states of molecules, as implemented in the MOLPRO system of ab initio programs, are reviewed. Recent improvements in the performance of the local method resulting from an implementation of the density-fitting technique for all electron-repulsion integrals are discussed. Local fitting approximations lead to linear scaling of CPU
Physical chemistry chemical physics : PCCP, Jan 21, 2014
In this work we simulate the diffraction peak intensities of He beams scattered on the MgO(100) s... more In this work we simulate the diffraction peak intensities of He beams scattered on the MgO(100) surface from first principles. It turns out that diffraction peak intensities are extremely sensitive to the quality of the potential describing the He-MgO surface interaction. Achieving the required accuracy in first principles calculations is very challenging indeed. The present work describes a first principles protocol able to achieve very high accuracy for reasonable computational cost. This method is based on periodic local second-order Møller-Plesset perturbation theory where systematic corrections for basis set truncation and for high-order electronic correlation are introduced using coupled cluster calculations on finite model systems mimicking the target system. For the He-MgO system the requirements with respect to the level of theory are very high; it turns out that contributions from connected quadruple excitations are non-negligible. Here we demonstrate that using this proto...
Journal of Molecular Structure: THEOCHEM, 1992
... Theochem), 276 (1992) 117-132 117 Elsevier Science Publishers BV, Amsterdam Structures and vi... more ... Theochem), 276 (1992) 117-132 117 Elsevier Science Publishers BV, Amsterdam Structures and vibrations of phenol "HgO and d-phenoI'DgO based on ab initio calculations Martin Schiitz, Thomas Burgi and Samuel Leutwyler Institut fur ... 26 CW Bock and M. Trachtman, J. Mol. ...