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Zlatko Bacic - One of the best experts on this subject based on the ideXlab platform.

  • flexible water molecule in c60 intramolecular vibrational frequencies and translation rotation eigenstates from fully coupled nine Dimensional quantum calculations with small basis sets
    Journal of Chemical Physics, 2020
    Co-Authors: Peter M Felker, Zlatko Bacic
    Abstract:

    We present a method for efficient calculation of intramolecular vibrational excitations of H2O inside C60, together with the low-energy intermolecular translation-rotation states within each intramolecular vibrational manifold. Apart from assuming rigid C60, this nine-Dimensional (9D) quantum treatment is fully coupled. Following the recently introduced approach [P. M. Felker and Z. Bacic, J. Chem. Phys. 151, 024305 (2019)], the full 9D vibrational Hamiltonian of H2O@C60 is partitioned into two reduced-dimension Hamiltonians, a 6D one for the intermolecular vibrations and another in 3D for the intramolecular degrees of freedom, and a 9D remainder term. The two reduced-dimension Hamiltonians are diagonalized, and their eigenvectors are used to build up a Product contracted basis in which the full vibrational Hamiltonian is diagonalized. The efficiency of this methodology derives from the insight of our earlier study referenced above that converged high-energy intramolecular vibrational excitations of weakly bound molecular complexes can be obtained from fully coupled quantum calculations where the full-Dimensional Product contracted basis includes only a small number of intermolecular vibrational eigenstates spanning the range of energies much below those of the intramolecular vibrational states of interest. In this study, the eigenstates included in the 6D intermolecular contacted basis extend to only 410 cm−1 above the ground state, which is much less than the H2O stretch and bend fundamentals, at ≈3700 and ≈1600 cm−1, respectively. The 9D calculations predict that the fundamentals of all three intramolecular modes, as well as the bend overtone, of the caged H2O are blueshifted relative to those of the gas-phase H2O, the two stretch modes much more so than the bend. Excitation of the bend mode affects the energies of the low-lying H2O rotational states significantly more than exciting either of the stretching modes. The center-of-mass translational fundamental is virtually unaffected by the excitation of any of the intramolecular vibrational modes. Further progress hinges on the experimental measurement of the vibrational frequency shifts in H2O@C60 and ab initio calculation of a high-quality 9D potential energy surface for this endohedral complex, neither of which is presently available.We present a method for efficient calculation of intramolecular vibrational excitations of H2O inside C60, together with the low-energy intermolecular translation-rotation states within each intramolecular vibrational manifold. Apart from assuming rigid C60, this nine-Dimensional (9D) quantum treatment is fully coupled. Following the recently introduced approach [P. M. Felker and Z. Bacic, J. Chem. Phys. 151, 024305 (2019)], the full 9D vibrational Hamiltonian of H2O@C60 is partitioned into two reduced-dimension Hamiltonians, a 6D one for the intermolecular vibrations and another in 3D for the intramolecular degrees of freedom, and a 9D remainder term. The two reduced-dimension Hamiltonians are diagonalized, and their eigenvectors are used to build up a Product contracted basis in which the full vibrational Hamiltonian is diagonalized. The efficiency of this methodology derives from the insight of our earlier study referenced above that converged high-energy intramolecular vibrational excitations of weakl...

  • flexible water molecule in c60 intramolecular vibrational frequencies and translation rotation eigenstates from fully coupled nine Dimensional quantum calculations with small basis sets
    Journal of Chemical Physics, 2020
    Co-Authors: Peter M Felker, Zlatko Bacic
    Abstract:

    We present a method for efficient calculation of intramolecular vibrational excitations of H2O inside C60, together with the low-energy intermolecular translation-rotation states within each intramolecular vibrational manifold. Apart from assuming rigid C60, this nine-Dimensional (9D) quantum treatment is fully coupled. Following the recently introduced approach [P. M. Felker and Z. Bacic, J. Chem. Phys. 151, 024305 (2019)], the full 9D vibrational Hamiltonian of H2O@C60 is partitioned into two reduced-dimension Hamiltonians, a 6D one for the intermolecular vibrations and another in 3D for the intramolecular degrees of freedom, and a 9D remainder term. The two reduced-dimension Hamiltonians are diagonalized, and their eigenvectors are used to build up a Product contracted basis in which the full vibrational Hamiltonian is diagonalized. The efficiency of this methodology derives from the insight of our earlier study referenced above that converged high-energy intramolecular vibrational excitations of weakly bound molecular complexes can be obtained from fully coupled quantum calculations where the full-Dimensional Product contracted basis includes only a small number of intermolecular vibrational eigenstates spanning the range of energies much below those of the intramolecular vibrational states of interest. In this study, the eigenstates included in the 6D intermolecular contacted basis extend to only 410 cm−1 above the ground state, which is much less than the H2O stretch and bend fundamentals, at ≈3700 and ≈1600 cm−1, respectively. The 9D calculations predict that the fundamentals of all three intramolecular modes, as well as the bend overtone, of the caged H2O are blueshifted relative to those of the gas-phase H2O, the two stretch modes much more so than the bend. Excitation of the bend mode affects the energies of the low-lying H2O rotational states significantly more than exciting either of the stretching modes. The center-of-mass translational fundamental is virtually unaffected by the excitation of any of the intramolecular vibrational modes. Further progress hinges on the experimental measurement of the vibrational frequency shifts in H2O@C60 and ab initio calculation of a high-quality 9D potential energy surface for this endohedral complex, neither of which is presently available.

Peter M Felker - One of the best experts on this subject based on the ideXlab platform.

  • flexible water molecule in c60 intramolecular vibrational frequencies and translation rotation eigenstates from fully coupled nine Dimensional quantum calculations with small basis sets
    Journal of Chemical Physics, 2020
    Co-Authors: Peter M Felker, Zlatko Bacic
    Abstract:

    We present a method for efficient calculation of intramolecular vibrational excitations of H2O inside C60, together with the low-energy intermolecular translation-rotation states within each intramolecular vibrational manifold. Apart from assuming rigid C60, this nine-Dimensional (9D) quantum treatment is fully coupled. Following the recently introduced approach [P. M. Felker and Z. Bacic, J. Chem. Phys. 151, 024305 (2019)], the full 9D vibrational Hamiltonian of H2O@C60 is partitioned into two reduced-dimension Hamiltonians, a 6D one for the intermolecular vibrations and another in 3D for the intramolecular degrees of freedom, and a 9D remainder term. The two reduced-dimension Hamiltonians are diagonalized, and their eigenvectors are used to build up a Product contracted basis in which the full vibrational Hamiltonian is diagonalized. The efficiency of this methodology derives from the insight of our earlier study referenced above that converged high-energy intramolecular vibrational excitations of weakly bound molecular complexes can be obtained from fully coupled quantum calculations where the full-Dimensional Product contracted basis includes only a small number of intermolecular vibrational eigenstates spanning the range of energies much below those of the intramolecular vibrational states of interest. In this study, the eigenstates included in the 6D intermolecular contacted basis extend to only 410 cm−1 above the ground state, which is much less than the H2O stretch and bend fundamentals, at ≈3700 and ≈1600 cm−1, respectively. The 9D calculations predict that the fundamentals of all three intramolecular modes, as well as the bend overtone, of the caged H2O are blueshifted relative to those of the gas-phase H2O, the two stretch modes much more so than the bend. Excitation of the bend mode affects the energies of the low-lying H2O rotational states significantly more than exciting either of the stretching modes. The center-of-mass translational fundamental is virtually unaffected by the excitation of any of the intramolecular vibrational modes. Further progress hinges on the experimental measurement of the vibrational frequency shifts in H2O@C60 and ab initio calculation of a high-quality 9D potential energy surface for this endohedral complex, neither of which is presently available.We present a method for efficient calculation of intramolecular vibrational excitations of H2O inside C60, together with the low-energy intermolecular translation-rotation states within each intramolecular vibrational manifold. Apart from assuming rigid C60, this nine-Dimensional (9D) quantum treatment is fully coupled. Following the recently introduced approach [P. M. Felker and Z. Bacic, J. Chem. Phys. 151, 024305 (2019)], the full 9D vibrational Hamiltonian of H2O@C60 is partitioned into two reduced-dimension Hamiltonians, a 6D one for the intermolecular vibrations and another in 3D for the intramolecular degrees of freedom, and a 9D remainder term. The two reduced-dimension Hamiltonians are diagonalized, and their eigenvectors are used to build up a Product contracted basis in which the full vibrational Hamiltonian is diagonalized. The efficiency of this methodology derives from the insight of our earlier study referenced above that converged high-energy intramolecular vibrational excitations of weakl...

  • flexible water molecule in c60 intramolecular vibrational frequencies and translation rotation eigenstates from fully coupled nine Dimensional quantum calculations with small basis sets
    Journal of Chemical Physics, 2020
    Co-Authors: Peter M Felker, Zlatko Bacic
    Abstract:

    We present a method for efficient calculation of intramolecular vibrational excitations of H2O inside C60, together with the low-energy intermolecular translation-rotation states within each intramolecular vibrational manifold. Apart from assuming rigid C60, this nine-Dimensional (9D) quantum treatment is fully coupled. Following the recently introduced approach [P. M. Felker and Z. Bacic, J. Chem. Phys. 151, 024305 (2019)], the full 9D vibrational Hamiltonian of H2O@C60 is partitioned into two reduced-dimension Hamiltonians, a 6D one for the intermolecular vibrations and another in 3D for the intramolecular degrees of freedom, and a 9D remainder term. The two reduced-dimension Hamiltonians are diagonalized, and their eigenvectors are used to build up a Product contracted basis in which the full vibrational Hamiltonian is diagonalized. The efficiency of this methodology derives from the insight of our earlier study referenced above that converged high-energy intramolecular vibrational excitations of weakly bound molecular complexes can be obtained from fully coupled quantum calculations where the full-Dimensional Product contracted basis includes only a small number of intermolecular vibrational eigenstates spanning the range of energies much below those of the intramolecular vibrational states of interest. In this study, the eigenstates included in the 6D intermolecular contacted basis extend to only 410 cm−1 above the ground state, which is much less than the H2O stretch and bend fundamentals, at ≈3700 and ≈1600 cm−1, respectively. The 9D calculations predict that the fundamentals of all three intramolecular modes, as well as the bend overtone, of the caged H2O are blueshifted relative to those of the gas-phase H2O, the two stretch modes much more so than the bend. Excitation of the bend mode affects the energies of the low-lying H2O rotational states significantly more than exciting either of the stretching modes. The center-of-mass translational fundamental is virtually unaffected by the excitation of any of the intramolecular vibrational modes. Further progress hinges on the experimental measurement of the vibrational frequency shifts in H2O@C60 and ab initio calculation of a high-quality 9D potential energy surface for this endohedral complex, neither of which is presently available.

Boris D Kudryashov - One of the best experts on this subject based on the ideXlab platform.

  • on suboptimum component decoding for Product codes
    International Symposium on Information Theory, 2006
    Co-Authors: Maja Loncar, Rolf Johannesson, Jossy Sayir, Irina E Bocharova, Boris D Kudryashov
    Abstract:

    The performance and convergence behavior of the iterative schemes for decoding two-Dimensional Product codes are investigated. The decoding trajectories of the extrinsic and the a posteriori information are used as a main tool for predicting and explaining the behavior of the iterative decoding process. The component-wise optimal BCJR decoder is compared to the suboptimal max-log-MAP decoder and the list-based BEAST-APP decoder in terms of convergence and bit-error-rate performance. The results are illustrated by examples, which show that the BEAST-APP decoder achieves near-BCJR performance with significantly lower complexity.

Yasuyuki Nogami - One of the best experts on this subject based on the ideXlab platform.

  • A Study on Low Level Quantizers for Block Turbo Decoding for Product Codes of Binary Linear Code
    2019 34th International Technical Conference on Circuits Systems Computers and Communications (ITC-CSCC), 2019
    Co-Authors: Shinichi Kageyama, Ken Ikuta, Takuya Kusaka, Yasuyuki Nogami
    Abstract:

    Block Turbo Decodings (BTDs) with Soft-In Soft-Out (SISO) decodings for two Dimensional Product codes of linear codes can achieve good error performance, however, large computational complexity of the BTDs can be a problem. Therefore, to reduce the computational complexity, quantization methods can be employed for the BTDs by sacrificing the error performance. In this paper, a study on design for low level quantizers for the BTD with SISO Ordered Statistics Decoding for Product codes of binary linear code is shown. From simulation results for a 4-level quantizer, the authors propose a new 5-level quantizer. The proposed 5-level quantizer achieves better error performance than 4-level quantizer.

  • An Analysis of Computational Complexity of Low Level Quantizers for Block Turbo Decoding for Product Codes of Binary Linear Code
    2019 Seventh International Symposium on Computing and Networking Workshops (CANDARW), 2019
    Co-Authors: Shinichi Kageyama, Ken Ikuta, Takuya Kusaka, Yuki Nanjo, Yuta Kodera, Yasuyuki Nogami
    Abstract:

    Block Turbo Decodings (BTDs) with Soft-In Soft-Out (SISO) decodings for two-Dimensional Product codes of linear codes can achieve good error performance. However, since large computational complexity of the BTDs can be a problem, a method which can reduce average computational complexity is needed. In this research, the authors focus on an early termination condition as the method for the reduction on the computational complexity. From the tendency of the output of SISO ordered statistics decoding, a condition is proposed. Based on simulation results for the two-Dimensional Product code of the (32,26,4) Reed-Muller code, analysis on a parameter of the condition are given. The results show that the computational complexity can be reduced to more than one fourth at the SN ratios higher than 7[dB] of Eb/No without degradation on error performance by choosing an appropriate parameter.

Fulong Jing - One of the best experts on this subject based on the ideXlab platform.

  • quadratic frequency modulation signals parameter estimation based on two Dimensional Product modified parameterized chirp rate quadratic chirp rate distribution
    Sensors, 2018
    Co-Authors: Changbo Hou, Fulong Jing
    Abstract:

    In an inverse synthetic aperture radar (ISAR) imaging system for targets with complex motion, the azimuth echo signals of the target are always modeled as multicomponent quadratic frequency modulation (QFM) signals. The chirp rate (CR) and quadratic chirp rate (QCR) estimation of QFM signals is very important to solve the ISAR image defocus problem. For multicomponent QFM (multi-QFM) signals, the conventional QR and QCR estimation algorithms suffer from the cross-term and poor anti-noise ability. This paper proposes a novel estimation algorithm called a two-Dimensional Product modified parameterized chirp rate-quadratic chirp rate distribution (2D-PMPCRD) for QFM signals parameter estimation. The 2D-PMPCRD employs a multi-scale parametric symmetric self-correlation function and modified nonuniform fast Fourier transform-Fast Fourier transform to transform the signals into the chirp rate-quadratic chirp rate (CR-QCR) domains. It can greatly suppress the cross-terms while strengthening the auto-terms by multiplying different CR-QCR domains with different scale factors. Compared with high order ambiguity function-integrated cubic phase function and modified Lv’s distribution, the simulation results verify that the 2D-PMPCRD acquires higher anti-noise performance and obtains better cross-terms suppression performance for multi-QFM signals with reasonable computation cost.