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Magdolna Hargittai - One of the best experts on this subject based on the ideXlab platform.
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quasilinear molecule par excellence srcl2 structure from high temperature gas phase electron diffraction and quantum chemical calculations computed structures of srcl2 argon complexes
Chemistry: A European Journal, 2006Co-Authors: Zoltan Varga, Giuseppe Lanza, Camilla Minichino, Magdolna HargittaiAbstract:The molecular geometry of strontium dichloride has been determined by high-temperature electron diffraction (ED) and computational techniques. The computation at the MP2 level of theory yields a shallow Bending Potential with a barrier of about 0.1 kcal mol(-1) at the linear configuration. The experimentally determined thermal average Sr--Cl bond length, r(g), is 2.625+/-0.010 A and the bond angle, angle-spherical(a), is 142.4+/-4.0 degrees . There is excellent agreement between the equilibrium bond lengths estimated from the experimental data, 2.607+/-0.013 A, and computed at different levels of theory and basis sets, 2.605+/-0.006 A. Based on anharmonic analyses of the symmetric and asymmetric stretching as well as the Bending motions of the molecule, we estimated the thermal average structure from the computation for the temperature of the ED experiment. In order to emulate the effect of the matrix environment on the measured vibrational frequencies, a series of complexes with argon atoms, SrCl(2)Ar(n) (n=1-7), with different geometrical arrangements were calculated. The complexes with six or seven argon atoms approximate the interaction best and the computed frequencies of these molecules are closer to the experimental ones than those computed for the free SrCl(2) molecule.
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quasilinear molecule par excellence srcl2 structure from high temperature gas phase electron diffraction and quantum chemical calculations computed structures of srcl2 argon complexes
Chemistry: A European Journal, 2006Co-Authors: Zoltan Varga, Giuseppe Lanza, Camilla Minichino, Magdolna HargittaiAbstract:The molecular geometry of strontium dichloride has been determined by high-temperature electron diffraction (ED) and computational techniques. The computation at the MP2 level of theory yields a shallow Bending Potential with a barrier of about 0.1 kcal mol -1 at the linear configuration. The experimentally determined thermal average Sr-Cl bond length, r g , is 2.625 ± 0.010 A and the bond angle,? a , is 142.4 ± 4.0°. There is excellent agreement between the equilibrium bond lengths estimated from the experimental data, 2.607 ± 0.013 A, and computed at different levels of theory and basis sets, 2.605 ± 0.006 A. Based on anharmonic analyses of the symmetric and asymmetric stretching as well as the Bending motions of the molecule, we estimated the thermal average structure from the computation for the temperature of the ED experiment. In order to emulate the effect of the matrix environment on the measured vibrational frequencies, a series of complexes with argon atoms, SrCl 2 ·Ar n (n=1-7), with different geometrical arrangements were calculated. The complexes with six or seven argon atoms approximate the interaction best and the computed frequencies of these molecules are closer to the experimental ones than those computed for the free SrCl 2 molecule.
Zoltan Varga - One of the best experts on this subject based on the ideXlab platform.
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quasilinear molecule par excellence srcl2 structure from high temperature gas phase electron diffraction and quantum chemical calculations computed structures of srcl2 argon complexes
Chemistry: A European Journal, 2006Co-Authors: Zoltan Varga, Giuseppe Lanza, Camilla Minichino, Magdolna HargittaiAbstract:The molecular geometry of strontium dichloride has been determined by high-temperature electron diffraction (ED) and computational techniques. The computation at the MP2 level of theory yields a shallow Bending Potential with a barrier of about 0.1 kcal mol(-1) at the linear configuration. The experimentally determined thermal average Sr--Cl bond length, r(g), is 2.625+/-0.010 A and the bond angle, angle-spherical(a), is 142.4+/-4.0 degrees . There is excellent agreement between the equilibrium bond lengths estimated from the experimental data, 2.607+/-0.013 A, and computed at different levels of theory and basis sets, 2.605+/-0.006 A. Based on anharmonic analyses of the symmetric and asymmetric stretching as well as the Bending motions of the molecule, we estimated the thermal average structure from the computation for the temperature of the ED experiment. In order to emulate the effect of the matrix environment on the measured vibrational frequencies, a series of complexes with argon atoms, SrCl(2)Ar(n) (n=1-7), with different geometrical arrangements were calculated. The complexes with six or seven argon atoms approximate the interaction best and the computed frequencies of these molecules are closer to the experimental ones than those computed for the free SrCl(2) molecule.
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quasilinear molecule par excellence srcl2 structure from high temperature gas phase electron diffraction and quantum chemical calculations computed structures of srcl2 argon complexes
Chemistry: A European Journal, 2006Co-Authors: Zoltan Varga, Giuseppe Lanza, Camilla Minichino, Magdolna HargittaiAbstract:The molecular geometry of strontium dichloride has been determined by high-temperature electron diffraction (ED) and computational techniques. The computation at the MP2 level of theory yields a shallow Bending Potential with a barrier of about 0.1 kcal mol -1 at the linear configuration. The experimentally determined thermal average Sr-Cl bond length, r g , is 2.625 ± 0.010 A and the bond angle,? a , is 142.4 ± 4.0°. There is excellent agreement between the equilibrium bond lengths estimated from the experimental data, 2.607 ± 0.013 A, and computed at different levels of theory and basis sets, 2.605 ± 0.006 A. Based on anharmonic analyses of the symmetric and asymmetric stretching as well as the Bending motions of the molecule, we estimated the thermal average structure from the computation for the temperature of the ED experiment. In order to emulate the effect of the matrix environment on the measured vibrational frequencies, a series of complexes with argon atoms, SrCl 2 ·Ar n (n=1-7), with different geometrical arrangements were calculated. The complexes with six or seven argon atoms approximate the interaction best and the computed frequencies of these molecules are closer to the experimental ones than those computed for the free SrCl 2 molecule.
Michael Zharnikov - One of the best experts on this subject based on the ideXlab platform.
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structure building forces in biphenyl substituted alkanethiolate self assembled monolayers on gaas 001 the effect of the Bending Potential
Journal of Physical Chemistry C, 2015Co-Authors: Michael ZharnikovAbstract:Molecular assembly on a technologically relevant GaAs substrate is an important and application-related issue. In this context, self-assembled monolayers (SAMs) formed from a series of ω-(4′-methylbiphenyl-4-yl)alkanethiols, CH3(C6H4)2(CH2)nSH (BPn, n = 1–6), were prepared on GaAs(001) and characterized in detail by high-resolution X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure spectroscopy. The resulting films exhibited pronounced, “odd–even” variation in molecular orientation and packing density with the number (n) of methylene groups in the alkyl linker; viz., smaller molecular inclination, associated with a higher packing density, was observed for an odd n, while the opposite was the case for an even n. Such an odd–even behavior confirms once again the existence of a Bending Potential for GaAs(001), which is equivalent to the analogous Potential for the Au(111) substrate, where similar odd–even behavior has been observed. This Potential plays an important role in the ba...
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Bending Potential as an important factor for the structure of monomolecular thiolate layers on gaas substrates
Journal of Physical Chemistry Letters, 2013Co-Authors: Andreas Terfort, Michael ZharnikovAbstract:The presence of a substrate-dependent binding geometry at the anchoring group and its energetics (Bending Potential) are known to be important in determining the lateral density and structure of self-assembled monolayers (SAMs) of thiolates and selenolates on coinage metal substrates. Here we show that on the technologically important GaAs(001) surface a Bending Potential exists for thiolate adlayers as well. For this, we used a series of terphenyl-substituted alkanethiols, C6H5(C6H4)2(CH2)nSH (TPn, n = 0–6), as a suitable model system. The Bending Potential plays a dominant role in the balance of the structure–building interactions in the TPn SAMs on GaAs, resulting in a persistent, “odd–even” variation of molecular orientation and packing density in these monolayers as a function of the parity of n. This observation should necessarily be considered for the design of future, functional SAMs on GaAs(001).
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effect of the Bending Potential on molecular arrangement in alkaneselenolate self assembled monolayers
Journal of Physical Chemistry C, 2008Co-Authors: Andrey Shaporenko, Jan Steffen Muller, Piotr Cyganik, Andreas Terfort, Martin Schmid, Michael ZharnikovAbstract:Self-assembled monolayers (SAMs) of hybrid 4,4′-biphenyl-substituted alkaneselenolates, CH3(C6H4)2(CH2)nSe(BPnSe) with a variable length of the aliphatic part (n ) 1-6, 10, 11) have been prepared on (111) gold and silver substrates and characterized by a variety of complementary experimental techniques. The packing density of the SAM constituents and the orientation of the biphenyl moieties were found to exhibit a pronounced “odd-even” variation with the number (n) of methylene units in the aliphatic linker of BPnSe moieties, which was opposite on silver as compared to gold. In particular, a smaller inclination and a corresponding higher packing density of the biphenyl moieties was observed for odd numbers of the methylene units in BPnSe/Au and for even numbers of these units in BPnSe/Ag. The observed odd-even effects were explained by a significant Bending Potential, favoring definite orientation of the metal-Se-C bond and entering the balance of the structure-building interactions either cooperatively or competitively. The existence of this Bending Potential is supposed to be closely related to the exact bonding configuration of the headgroup atom, with the optimal substrate-Se-C angles being different for Au and Ag substrates. In view of the analogous behavior of thiolate-based systems, one can assume a common origin of the observed phenomena in chalcogen-based SAMs, in both of which the bonding configuration of the headgroup seems to be an important or even deciding factor in the balance of structure-building interactions.
Camilla Minichino - One of the best experts on this subject based on the ideXlab platform.
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quasilinear molecule par excellence srcl2 structure from high temperature gas phase electron diffraction and quantum chemical calculations computed structures of srcl2 argon complexes
Chemistry: A European Journal, 2006Co-Authors: Zoltan Varga, Giuseppe Lanza, Camilla Minichino, Magdolna HargittaiAbstract:The molecular geometry of strontium dichloride has been determined by high-temperature electron diffraction (ED) and computational techniques. The computation at the MP2 level of theory yields a shallow Bending Potential with a barrier of about 0.1 kcal mol(-1) at the linear configuration. The experimentally determined thermal average Sr--Cl bond length, r(g), is 2.625+/-0.010 A and the bond angle, angle-spherical(a), is 142.4+/-4.0 degrees . There is excellent agreement between the equilibrium bond lengths estimated from the experimental data, 2.607+/-0.013 A, and computed at different levels of theory and basis sets, 2.605+/-0.006 A. Based on anharmonic analyses of the symmetric and asymmetric stretching as well as the Bending motions of the molecule, we estimated the thermal average structure from the computation for the temperature of the ED experiment. In order to emulate the effect of the matrix environment on the measured vibrational frequencies, a series of complexes with argon atoms, SrCl(2)Ar(n) (n=1-7), with different geometrical arrangements were calculated. The complexes with six or seven argon atoms approximate the interaction best and the computed frequencies of these molecules are closer to the experimental ones than those computed for the free SrCl(2) molecule.
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quasilinear molecule par excellence srcl2 structure from high temperature gas phase electron diffraction and quantum chemical calculations computed structures of srcl2 argon complexes
Chemistry: A European Journal, 2006Co-Authors: Zoltan Varga, Giuseppe Lanza, Camilla Minichino, Magdolna HargittaiAbstract:The molecular geometry of strontium dichloride has been determined by high-temperature electron diffraction (ED) and computational techniques. The computation at the MP2 level of theory yields a shallow Bending Potential with a barrier of about 0.1 kcal mol -1 at the linear configuration. The experimentally determined thermal average Sr-Cl bond length, r g , is 2.625 ± 0.010 A and the bond angle,? a , is 142.4 ± 4.0°. There is excellent agreement between the equilibrium bond lengths estimated from the experimental data, 2.607 ± 0.013 A, and computed at different levels of theory and basis sets, 2.605 ± 0.006 A. Based on anharmonic analyses of the symmetric and asymmetric stretching as well as the Bending motions of the molecule, we estimated the thermal average structure from the computation for the temperature of the ED experiment. In order to emulate the effect of the matrix environment on the measured vibrational frequencies, a series of complexes with argon atoms, SrCl 2 ·Ar n (n=1-7), with different geometrical arrangements were calculated. The complexes with six or seven argon atoms approximate the interaction best and the computed frequencies of these molecules are closer to the experimental ones than those computed for the free SrCl 2 molecule.
Giuseppe Lanza - One of the best experts on this subject based on the ideXlab platform.
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quasilinear molecule par excellence srcl2 structure from high temperature gas phase electron diffraction and quantum chemical calculations computed structures of srcl2 argon complexes
Chemistry: A European Journal, 2006Co-Authors: Zoltan Varga, Giuseppe Lanza, Camilla Minichino, Magdolna HargittaiAbstract:The molecular geometry of strontium dichloride has been determined by high-temperature electron diffraction (ED) and computational techniques. The computation at the MP2 level of theory yields a shallow Bending Potential with a barrier of about 0.1 kcal mol(-1) at the linear configuration. The experimentally determined thermal average Sr--Cl bond length, r(g), is 2.625+/-0.010 A and the bond angle, angle-spherical(a), is 142.4+/-4.0 degrees . There is excellent agreement between the equilibrium bond lengths estimated from the experimental data, 2.607+/-0.013 A, and computed at different levels of theory and basis sets, 2.605+/-0.006 A. Based on anharmonic analyses of the symmetric and asymmetric stretching as well as the Bending motions of the molecule, we estimated the thermal average structure from the computation for the temperature of the ED experiment. In order to emulate the effect of the matrix environment on the measured vibrational frequencies, a series of complexes with argon atoms, SrCl(2)Ar(n) (n=1-7), with different geometrical arrangements were calculated. The complexes with six or seven argon atoms approximate the interaction best and the computed frequencies of these molecules are closer to the experimental ones than those computed for the free SrCl(2) molecule.
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quasilinear molecule par excellence srcl2 structure from high temperature gas phase electron diffraction and quantum chemical calculations computed structures of srcl2 argon complexes
Chemistry: A European Journal, 2006Co-Authors: Zoltan Varga, Giuseppe Lanza, Camilla Minichino, Magdolna HargittaiAbstract:The molecular geometry of strontium dichloride has been determined by high-temperature electron diffraction (ED) and computational techniques. The computation at the MP2 level of theory yields a shallow Bending Potential with a barrier of about 0.1 kcal mol -1 at the linear configuration. The experimentally determined thermal average Sr-Cl bond length, r g , is 2.625 ± 0.010 A and the bond angle,? a , is 142.4 ± 4.0°. There is excellent agreement between the equilibrium bond lengths estimated from the experimental data, 2.607 ± 0.013 A, and computed at different levels of theory and basis sets, 2.605 ± 0.006 A. Based on anharmonic analyses of the symmetric and asymmetric stretching as well as the Bending motions of the molecule, we estimated the thermal average structure from the computation for the temperature of the ED experiment. In order to emulate the effect of the matrix environment on the measured vibrational frequencies, a series of complexes with argon atoms, SrCl 2 ·Ar n (n=1-7), with different geometrical arrangements were calculated. The complexes with six or seven argon atoms approximate the interaction best and the computed frequencies of these molecules are closer to the experimental ones than those computed for the free SrCl 2 molecule.