The Experts below are selected from a list of 117 Experts worldwide ranked by ideXlab platform
Stephen G. Kukolich - One of the best experts on this subject based on the ideXlab platform.
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Deuterium Quadrupole Coupling in the gas phase
Molecular Physics, 2016Co-Authors: Stephen G. KukolichAbstract:Recent measurements of deuterium Quadrupole Coupling in the gas phase are reviewed. Most of the results presented were obtained using molecular beam maser spectrometers and this type of apparatus is discussed briefly. Variations in the Quadrupole Coupling strength for changes in the adjacent atom and bond order are discussed. The relation between electric field gradients and stretching force constants is examined in terms of the experimental data.
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microwave measurements of 14n and d Quadrupole Coupling for z 2 hydroxypyridine and 2 pyridone tautomers
Journal of Physical Chemistry A, 2004Co-Authors: Chakree Tanjaroon, Ranga Subramanian, Chandana Karunatilaka, Stephen G. KukolichAbstract:Rotational spectra for the two tautomers (Z)-2-hydroxypyridine and 2-pyridone and their deuterated isotopomers were measured in the microwave range between 4 and 14 GHz using a pulsed beam Fourier transform microwave spectrometer. Nitrogen and deuterium Quadrupole hyperfine structure was completely resolved for many of the observed transitions, and the measured 14N Quadrupole Coupling tensors are quite different for these two tautomers. The eQqcc(N) values have opposite signs. The 14N Quadrupole Coupling strengths for (Z)-2-hydroxypyridine in the principal inertial axis system are as follows: eQqaa(N) = −0.076(11), eQqbb(N) = −2.283(6), and eQqcc(N) = 2.359(6) MHz. The 14N and D nuclear Quadrupole Coupling strengths for (Z)-2-deuteriohydroxypyridine in the principal inertial axis are eQqaa(N) = −0.1465(4), eQqbb(N) = −2.2045(4), and eQqcc(N) = 2.3510(4) MHz and eQqaa(D) = −0.0250(9), eQqbb(D) = 0.1699(4), and eQqcc(D) = −0.1449(4) MHz. The 14N Quadrupole Coupling strengths for 2-pyridone in the principal...
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measurements of structural and Quadrupole Coupling parameters for bromoferrocene using microwave spectroscopy
Journal of Chemical Physics, 1997Co-Authors: Brian J Drouin, Greg T Lavaty, P A Cassak, Stephen G. KukolichAbstract:Rotational spectra for two isotopomers of bromoferrocene were measured using pulsed-beam Fourier transform microwave spectroscopy. Transitions were observed for the 79Br and 81Br isotopomers in the 5–9 GHz range. Rotational constants and the Quadrupole Coupling tensors were obtained from the data. The rotational constants and Quadrupole Coupling parameters for 79Br are A=1272.110(1), B=516.1125(2), C=441.3775(2), eQqaa=267.16(3), eQqab=−409.81(4), and eQqbb=21.49(4), and those for 81Br are A=1271.045(4), B=510.0079(2), C=436.7687(2), eQqaa=225.40(6), eQqab=−341.62(4), and eQqbb=15.65(4). The measured rotational constants were used to determine the following structural parameters of bromoferrocene: r(Fe–(C5H5))=1.63(2), r(Fe–(C5H4Br))=1.67(3), r(C–Br)=1.875(11), and r(C–C)=1.433(1) A. The values of the Quadrupole Coupling parameters in the principal Quadrupole axis systems and the C–Br bond axis systems are compared with similarly derived parameters for chloroferrocene, chlorobenzene, and bromobenzene. Pre...
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Rotational transition and Quadrupole Coupling measurements on the NNO-HCN complex
Chemical Physics Letters, 1990Co-Authors: D. J. Pauley, M. A. Roehrig, Stephen G. KukolichAbstract:Abstract Seven a -dipole and seven b -dipole transitions were measured for one isomer of the NNO-HCN complex using a pulsed-beam, Fourier transform microwave spectrometer. Rotational constants A +Δ K =10326.3(4) MHz, B =2814.32(14) MHz and C =2201.00(12) MHz and distortion constants Δ J =0.014(8) MHz and Δ JK =0.14(6) MHz were obtained by fitting the observed transition frequencies. A Quadrupole Coupling strength due to the HCN nitrogen of eQq aa =1.97±0.05 MHz was obtained by fitting low- J transitions. Approximate structural parameters are obtained using moments of inertia and Quadrupole Coupling data.
Jochen Kupper - One of the best experts on this subject based on the ideXlab platform.
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the effect of nuclear Quadrupole Coupling in the laser induced alignment of molecules
Journal of Physical Chemistry A, 2020Co-Authors: Linda V Thesing, Andrey Yachmenev, Rosario Gonzalezferez, Jochen KupperAbstract:We present a theoretical study of the time-dependent laser alignment of molecules taking into account the hyperfine Coupling due to nuclear-Quadrupole interactions. The Coupling of nuclear spins to the overall angular momentum of molecules significantly influences their rotational dynamics. Here, we systematically analyze the impact of the nuclear-Quadrupole Coupling on the rotational dynamics of the linear I2 and the asymmetric-top diiodobenzene molecule induced by external laser fields. We explore different regimes of pulse shapes and laser-pulse intensities and detail under which conditions the Quadrupole Coupling cannot be neglected in the description of the laser alignment of molecules.
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laser induced dynamics of molecules with strong nuclear Quadrupole Coupling
Journal of Chemical Physics, 2019Co-Authors: Andrey Yachmenev, Linda V Thesing, Jochen KupperAbstract:We present a general variational approach for computing the laser-induced rovibrational dynamics of molecules, taking into account the hyperfine effects of the nuclear Quadrupole Coupling. The method combines the general variational approach TROVE (Theoretical Ro-Vibrational Energies), which provides accurate rovibrational hyperfine energies and wavefunctions for arbitrary molecules, with the variational method RichMol, designed for generalized simulations of the rovibrational dynamics in the presence of external electric fields. We investigate the effect of the nuclear Quadrupole Coupling on the short-pulse laser alignment of a prototypical molecule CFClBrI, which contains nuclei with large Quadrupole constants. The influence of the nuclear Quadrupole interactions on the postpulse molecular dynamics is negligible at early times, for the first several revivals; however, at longer time scales, the effect is entirely detrimental and strongly depends on the laser intensity. This effect can be explained by dephasing in the laser-excited rotational wavepacket due to irregular spacings between the hyperfine-split nuclear spin states across different rotational hyperfine bands.We present a general variational approach for computing the laser-induced rovibrational dynamics of molecules, taking into account the hyperfine effects of the nuclear Quadrupole Coupling. The method combines the general variational approach TROVE (Theoretical Ro-Vibrational Energies), which provides accurate rovibrational hyperfine energies and wavefunctions for arbitrary molecules, with the variational method RichMol, designed for generalized simulations of the rovibrational dynamics in the presence of external electric fields. We investigate the effect of the nuclear Quadrupole Coupling on the short-pulse laser alignment of a prototypical molecule CFClBrI, which contains nuclei with large Quadrupole constants. The influence of the nuclear Quadrupole interactions on the postpulse molecular dynamics is negligible at early times, for the first several revivals; however, at longer time scales, the effect is entirely detrimental and strongly depends on the laser intensity. This effect can be explained by de...
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laser induced dynamics of molecules with strong nuclear Quadrupole Coupling
arXiv: Atomic and Molecular Clusters, 2019Co-Authors: Andrey Yachmenev, Linda V Thesing, Jochen KupperAbstract:We present a general variational approach for computing the laser-induced rovibrational dynamics of molecules taking into account the hyperfine effects of the nuclear Quadrupole Coupling. The method combines the general variational approach TROVE, which provides accurate rovibrational hyperfine energies and wave functions for arbitrary molecules, with the variational method RichMol, designed for generalized simulations of the rovibrational dynamics in the presence of external electric fields. We investigate the effect of the nuclear Quadrupole Coupling on the short-pulse laser alignment of a prototypical molecule CFClBrI, which contains nuclei with large Quadrupole constants. The influence of the nuclear Quadrupole interactions on the post-pulse molecular dynamics is negligible at early times, first several revivals, however at longer timescales the effect is entirely detrimental and strongly depends on the laser intensity. This effect can be explained by dephasing in the laser-excited rotational wavepacket due to irregular spacings between the hyperfine-split nuclear spin states across different rotational hyperfine bands.
Gang Wu - One of the best experts on this subject based on the ideXlab platform.
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a modified townes dailey model for interpretation and visualization of nuclear Quadrupole Coupling tensors in molecules
Journal of Physical Chemistry A, 2020Co-Authors: Andrew Rinald, Gang WuAbstract:: We propose a modified Townes-Dailey (TD) model to help interpret and visualize experimentally measurable nuclear Quadrupole Coupling tensors (thus the electric field gradient tensors) in molecules. We show that within the framework of the TD model each principal component of the nuclear Quadrupole Coupling tensor is directly related to a new quantity termed as the valence p-orbital population anisotropy (VPPA or ΔP) in the same direction. Although the proposed model is a simple reformulation of the original TD model thus does not introduce new physics, the concept of VPPA makes it possible to directly interpret as well as visualize in a much straightforward way the experimentally determined nuclear Quadrupole Coupling tensors in molecules. We illustrate the utilization of VPPA using nuclear Quadrupole Coupling tensors for 11B, 14N, 17O, 35Cl, 79Br, and 127I nuclei in a variety of molecules. We propose to use VPPA or ΔP ellipsoid representation as a means of visualizing/displaying nuclear Quadrupole Coupling tensors in the molecular frame. We show the usefulness of the VPPA concept in providing a unifying explanation for seemingly different types of molecular interactions such as hydrogen bonding, halogen bonding, and frustrated Lewis pairs. We further suggest that VPPA can be used as a universal measure of the ability of any element in the entire p-block of the periodic table (groups 13-16) to interact with nucleophiles (e.g., formation of chalcogen, pnictogen, tetrel, and triel bonds).
Stewart E Novick - One of the best experts on this subject based on the ideXlab platform.
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Determination and analysis of the nuclear Quadrupole Coupling tensors of 2-bromopyridine
Journal of Molecular Spectroscopy, 2019Co-Authors: Angela Y. Chung, Eric A. Arsenault, Susanna Stephens, Wallace C. Pringle, Carlos A. Jiménez-hoyos, S.a. Cooke, Stewart E NovickAbstract:Abstract The rotational spectrum of 2-bromopyridine was reinvestigated in the frequency range of 10–15.5 GHz by Fourier transform microwave (FTMW) spectroscopy. New observations of 14N hyperfine splittings have been observed for both the bromine-79 and -81 isotopologues in addition to five centrifugal distortion constants. Rotational constants and bromine nuclear Quadrupole Coupling tensors have been refined. Both the bromine and the nitrogen nuclear Quadrupole Coupling tensors have been investigated using the Extended Townes-Dailey analysis.
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extended townes dailey analysis of the nuclear Quadrupole Coupling tensor
Journal of Molecular Spectroscopy, 2011Co-Authors: Stewart E NovickAbstract:Abstract One simple way to understand nuclear Quadrupole Coupling constants is by invoking the model of Townes and Dailey. This model, involving the field gradients generated by p electrons, has usually been used to estimate the fractional ionic character of diatomic molecules from a single nuclear Quadrupole Coupling constant. We will extend the model to three dimensions for polyatomic molecules. We will consider the case of molecules with unhybridized orbitals and molecules containing second row atoms whose orbitals are best thought of as hybridized.
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Extended Townes–Dailey analysis of the nuclear Quadrupole Coupling tensor
Journal of Molecular Spectroscopy, 2011Co-Authors: Stewart E NovickAbstract:Abstract One simple way to understand nuclear Quadrupole Coupling constants is by invoking the model of Townes and Dailey. This model, involving the field gradients generated by p electrons, has usually been used to estimate the fractional ionic character of diatomic molecules from a single nuclear Quadrupole Coupling constant. We will extend the model to three dimensions for polyatomic molecules. We will consider the case of molecules with unhybridized orbitals and molecules containing second row atoms whose orbitals are best thought of as hybridized.
Andrey Yachmenev - One of the best experts on this subject based on the ideXlab platform.
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the effect of nuclear Quadrupole Coupling in the laser induced alignment of molecules
Journal of Physical Chemistry A, 2020Co-Authors: Linda V Thesing, Andrey Yachmenev, Rosario Gonzalezferez, Jochen KupperAbstract:We present a theoretical study of the time-dependent laser alignment of molecules taking into account the hyperfine Coupling due to nuclear-Quadrupole interactions. The Coupling of nuclear spins to the overall angular momentum of molecules significantly influences their rotational dynamics. Here, we systematically analyze the impact of the nuclear-Quadrupole Coupling on the rotational dynamics of the linear I2 and the asymmetric-top diiodobenzene molecule induced by external laser fields. We explore different regimes of pulse shapes and laser-pulse intensities and detail under which conditions the Quadrupole Coupling cannot be neglected in the description of the laser alignment of molecules.
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laser induced dynamics of molecules with strong nuclear Quadrupole Coupling
Journal of Chemical Physics, 2019Co-Authors: Andrey Yachmenev, Linda V Thesing, Jochen KupperAbstract:We present a general variational approach for computing the laser-induced rovibrational dynamics of molecules, taking into account the hyperfine effects of the nuclear Quadrupole Coupling. The method combines the general variational approach TROVE (Theoretical Ro-Vibrational Energies), which provides accurate rovibrational hyperfine energies and wavefunctions for arbitrary molecules, with the variational method RichMol, designed for generalized simulations of the rovibrational dynamics in the presence of external electric fields. We investigate the effect of the nuclear Quadrupole Coupling on the short-pulse laser alignment of a prototypical molecule CFClBrI, which contains nuclei with large Quadrupole constants. The influence of the nuclear Quadrupole interactions on the postpulse molecular dynamics is negligible at early times, for the first several revivals; however, at longer time scales, the effect is entirely detrimental and strongly depends on the laser intensity. This effect can be explained by dephasing in the laser-excited rotational wavepacket due to irregular spacings between the hyperfine-split nuclear spin states across different rotational hyperfine bands.We present a general variational approach for computing the laser-induced rovibrational dynamics of molecules, taking into account the hyperfine effects of the nuclear Quadrupole Coupling. The method combines the general variational approach TROVE (Theoretical Ro-Vibrational Energies), which provides accurate rovibrational hyperfine energies and wavefunctions for arbitrary molecules, with the variational method RichMol, designed for generalized simulations of the rovibrational dynamics in the presence of external electric fields. We investigate the effect of the nuclear Quadrupole Coupling on the short-pulse laser alignment of a prototypical molecule CFClBrI, which contains nuclei with large Quadrupole constants. The influence of the nuclear Quadrupole interactions on the postpulse molecular dynamics is negligible at early times, for the first several revivals; however, at longer time scales, the effect is entirely detrimental and strongly depends on the laser intensity. This effect can be explained by de...
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laser induced dynamics of molecules with strong nuclear Quadrupole Coupling
arXiv: Atomic and Molecular Clusters, 2019Co-Authors: Andrey Yachmenev, Linda V Thesing, Jochen KupperAbstract:We present a general variational approach for computing the laser-induced rovibrational dynamics of molecules taking into account the hyperfine effects of the nuclear Quadrupole Coupling. The method combines the general variational approach TROVE, which provides accurate rovibrational hyperfine energies and wave functions for arbitrary molecules, with the variational method RichMol, designed for generalized simulations of the rovibrational dynamics in the presence of external electric fields. We investigate the effect of the nuclear Quadrupole Coupling on the short-pulse laser alignment of a prototypical molecule CFClBrI, which contains nuclei with large Quadrupole constants. The influence of the nuclear Quadrupole interactions on the post-pulse molecular dynamics is negligible at early times, first several revivals, however at longer timescales the effect is entirely detrimental and strongly depends on the laser intensity. This effect can be explained by dephasing in the laser-excited rotational wavepacket due to irregular spacings between the hyperfine-split nuclear spin states across different rotational hyperfine bands.