Long-Range Potential

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Xiaolong Zhang - One of the best experts on this subject based on the ideXlab platform.

  • analytic morse long range Potential energy surfaces and adiabatic hindered rotor treatment for a symmetric top linear molecule dimer a case study of ch3f h2
    2018
    Co-Authors: Xiaolong Zhang, Yu Zhai
    Abstract:

    A first effective six-dimensional ab initio Potential energy surface (PES) for CH3F–H2 which explicitly includes the intramolecular Q3 stretching normal mode of the CH3F monomer is presented. The electronic structure computations have been carried out at the explicitly correlated coupled cluster level of theory [CCSD(T)-F12a] with an augmented correlation-consistent triple zeta basis set. Five-dimensional analytical intermolecular PESs for ν3(CH3F) = 0 and 1 are then obtained by fitting the vibrationally averaged Potentials to the Morse/Long-Range (MLR) Potential function form. The MLR function form is applied to the nonlinear molecule-linear molecule case for the first time. These fits to 25 015 points have root-mean-square deviations of 0.74 cm−1 and 0.082 cm−1 for interaction energies less than 0.0 cm−1. Using the adiabatic hindered-rotor approximation, three-dimensional PESs for CH3F–paraH2 are generated from the 5D PESs over all possible orientations of the hydrogen monomer. The infrared and microwave spectra for CH3F–paraH2 dimer are predicted for the first time. These analytic PESs can be used for modeling the dynamical behavior in CH3F–(H2)N clusters, including the possible appearance of microscopic superfluidity.

  • analytic morse long range Potential energy surfaces and adiabatic hindered rotor treatment for a symmetric top linear molecule dimer a case study of ch3f h2
    2018
    Co-Authors: Xiaolong Zhang, Yu Zhai
    Abstract:

    A first effective six-dimensional ab initio Potential energy surface (PES) for CH3F–H2 which explicitly includes the intramolecular Q3 stretching normal mode of the CH3F monomer is presented. The electronic structure computations have been carried out at the explicitly correlated coupled cluster level of theory [CCSD(T)-F12a] with an augmented correlation-consistent triple zeta basis set. Five-dimensional analytical intermolecular PESs for ν3(CH3F) = 0 and 1 are then obtained by fitting the vibrationally averaged Potentials to the Morse/Long-Range (MLR) Potential function form. The MLR function form is applied to the nonlinear molecule-linear molecule case for the first time. These fits to 25 015 points have root-mean-square deviations of 0.74 cm−1 and 0.082 cm−1 for interaction energies less than 0.0 cm−1. Using the adiabatic hindered-rotor approximation, three-dimensional PESs for CH3F–paraH2 are generated from the 5D PESs over all possible orientations of the hydrogen monomer. The infrared and microwave spectra for CH3F–paraH2 dimer are predicted for the first time. These analytic PESs can be used for modeling the dynamical behavior in CH3F–(H2)N clusters, including the possible appearance of microscopic superfluidity.A first effective six-dimensional ab initio Potential energy surface (PES) for CH3F–H2 which explicitly includes the intramolecular Q3 stretching normal mode of the CH3F monomer is presented. The electronic structure computations have been carried out at the explicitly correlated coupled cluster level of theory [CCSD(T)-F12a] with an augmented correlation-consistent triple zeta basis set. Five-dimensional analytical intermolecular PESs for ν3(CH3F) = 0 and 1 are then obtained by fitting the vibrationally averaged Potentials to the Morse/Long-Range (MLR) Potential function form. The MLR function form is applied to the nonlinear molecule-linear molecule case for the first time. These fits to 25 015 points have root-mean-square deviations of 0.74 cm−1 and 0.082 cm−1 for interaction energies less than 0.0 cm−1. Using the adiabatic hindered-rotor approximation, three-dimensional PESs for CH3F–paraH2 are generated from the 5D PESs over all possible orientations of the hydrogen monomer. The infrared and microwav...

  • intermolecular configurations dominated by quadrupole quadrupole electrostatic interactions explicit correlation treatment of the five dimensional Potential energy surface and infrared spectra for the co n2 complex
    2018
    Co-Authors: Jingmin Liu, Yu Zhai, Xiaolong Zhang
    Abstract:

    A thorough understanding of the intermolecular configurations of van der Waals complexes is a great challenge due to their weak interactions, floppiness and anharmonic nature. Although high-resolution microwave or infrared spectroscopy provides one of the most direct and precise pieces of experimental evidence, the origin and key role in determining such intermolecular configurations of a van der Waals system strongly depend on its highly accurate Potential energy surface (PES) and a detailed analysis of its ro-vibrational wavefunctions. Here, a new five-dimensional Potential energy surface for the van der Waals complex of CO–N2 which explicitly incorporates the dependence on the stretch coordinate of the CO monomer is generated using the explicitly correlated couple cluster (CCSD(T)-F12) method in conjunction with a large basis set. Analytic four-dimensional PESs are obtained by the least-squares fitting of vibrationally averaged interaction energies for v = 0 and v = 1 to the Morse/Long-Range Potential mode (VMLR). These fits to 7966 points have root-mean-square deviations (RMSD) of 0.131 cm−1 and 0.129 cm−1 for v = 0 and v = 1, respectively, with only 315 parameters. Energy decomposition analysis is carried out, and it reveals that the dominant factor in controlling intermolecular configurations is quadrupole–quadrupole electrostatic interactions. Moreover, the rovibrational levels and wave functions are obtained for the first time. The predicted infrared transitions and intensities for the ortho-N2–CO complex as well as the calculated energy levels for para-N2–CO are in good agreement with the available experimental data with RMSD discrepancies smaller than 0.068 cm−1. The calculated infrared band origin shift associated with the fundamental band frequency of CO is −0.721 cm−1 for ortho-N2–CO which is in excellent agreement with the experimental value of −0.739 cm−1. The agreement with experimental values validates the high quality of the PESs and enhances our confidence to explain the observed mystery lines around 2163 cm−1.

  • the origins of intra and inter molecular vibrational couplings a case study of h2o ar on full and reduced dimensional Potential energy surface
    2016
    Co-Authors: Dan Hou, Xiaolong Zhang
    Abstract:

    The origin and strength of intra- and inter-molecular vibrational coupling is difficult to probe by direct experimental observations. However, explicitly including or not including some specific intramolecular vibrational modes to study intermolecular interaction provides a precise theoretical way to examine the effects of anharmonic coupling between modes. In this work, a full-dimension intra- and inter-molecular ab initio Potential energy surface (PES) for H2O-Ar, which explicitly incorporates interdependence on the intramolecular (Q1,  Q2,  Q3) normal-mode coordinates of the H2O monomer, has been calculated. In addition, four analytic vibrational-quantum-state-specific PESs are obtained by least-squares fitting vibrationally averaged interaction energies for the (v1,  v2,  v3) =  (0,  0,  0), (0,  0,  1), (1,  0,  0), (0,  1,  0) states of H2O to the three-dimensional Morse/Long-Range Potential function. Each vibrationally averaged PES fitted to 442 points has root-mean-square (rms) deviation smaller than 0.15 cm(-1), and required only 58 parameters. With the 3D PESs of H2O-Ar dimer system, we employed the combined radial discrete variable representation/angular finite basis representation method and Lanczos algorithm to calculate rovibrational energy levels. This showed that the resulting vibrationally averaged PESs provide good representations of the experimental infrared data, with rms discrepancies smaller than 0.02 cm(-1) for all three rotational branches of the asymmetric stretch fundamental transitions. The infrared band origin shifts associated with three fundamental bands of H2O in H2O-Ar complex are predicted for the first time and are found to be in good agreement with the (extrapolated) experimental values. Upon introduction of additional intramolecular degrees of freedom into the intermolecular Potential energy surface, there is clear spectroscopic evidence of intra- and intermolecular vibrational couplings.

  • analytic morse long range Potential energy surfaces and predicted infrared spectra for co h2 dimer and frequency shifts of co in para h2 n n 1 20 clusters
    2013
    Co-Authors: Xiaolong Zhang, Robert Le J Roy, Pierrenicholas Roy
    Abstract:

    A five-dimensional ab initio Potential energy surface (PES) for CO–H2 that explicitly incorporates dependence on the stretch coordinate of the CO monomer has been calculated. Analytic four-dimensional PESs are obtained by least-squares fitting vibrationally averaged interaction energies for  vCO = 0  and 1 to the Morse/Long-Range Potential function form. These fits to 30 206 points have root-mean-square (RMS) deviations of 0.087 and 0.082 cm−1, and require only 196 parameters. The resulting vibrationally averaged PESs provide good representations of the experimental infrared data: for infrared transitions of para H2–CO and ortho H2–CO, the RMS discrepancies are only 0.007 and 0.023 cm−1, which are almost in the same accuracy as those values of 0.010 and 0.018 cm−1 obtained from full six-dimensional ab initio PESs of V12 [P. Jankowski, A. R. W. McKellar, and K. Szalewicz, Science 336, 1147 (2012)]. The calculated infrared band origin shift associated with the fundamental of CO is −0.179 cm−1 for para H2–CO...

A M Lyyra - One of the best experts on this subject based on the ideXlab platform.

Yu Zhai - One of the best experts on this subject based on the ideXlab platform.

  • analytic morse long range Potential energy surfaces and adiabatic hindered rotor treatment for a symmetric top linear molecule dimer a case study of ch3f h2
    2018
    Co-Authors: Xiaolong Zhang, Yu Zhai
    Abstract:

    A first effective six-dimensional ab initio Potential energy surface (PES) for CH3F–H2 which explicitly includes the intramolecular Q3 stretching normal mode of the CH3F monomer is presented. The electronic structure computations have been carried out at the explicitly correlated coupled cluster level of theory [CCSD(T)-F12a] with an augmented correlation-consistent triple zeta basis set. Five-dimensional analytical intermolecular PESs for ν3(CH3F) = 0 and 1 are then obtained by fitting the vibrationally averaged Potentials to the Morse/Long-Range (MLR) Potential function form. The MLR function form is applied to the nonlinear molecule-linear molecule case for the first time. These fits to 25 015 points have root-mean-square deviations of 0.74 cm−1 and 0.082 cm−1 for interaction energies less than 0.0 cm−1. Using the adiabatic hindered-rotor approximation, three-dimensional PESs for CH3F–paraH2 are generated from the 5D PESs over all possible orientations of the hydrogen monomer. The infrared and microwave spectra for CH3F–paraH2 dimer are predicted for the first time. These analytic PESs can be used for modeling the dynamical behavior in CH3F–(H2)N clusters, including the possible appearance of microscopic superfluidity.A first effective six-dimensional ab initio Potential energy surface (PES) for CH3F–H2 which explicitly includes the intramolecular Q3 stretching normal mode of the CH3F monomer is presented. The electronic structure computations have been carried out at the explicitly correlated coupled cluster level of theory [CCSD(T)-F12a] with an augmented correlation-consistent triple zeta basis set. Five-dimensional analytical intermolecular PESs for ν3(CH3F) = 0 and 1 are then obtained by fitting the vibrationally averaged Potentials to the Morse/Long-Range (MLR) Potential function form. The MLR function form is applied to the nonlinear molecule-linear molecule case for the first time. These fits to 25 015 points have root-mean-square deviations of 0.74 cm−1 and 0.082 cm−1 for interaction energies less than 0.0 cm−1. Using the adiabatic hindered-rotor approximation, three-dimensional PESs for CH3F–paraH2 are generated from the 5D PESs over all possible orientations of the hydrogen monomer. The infrared and microwav...

  • analytic morse long range Potential energy surfaces and adiabatic hindered rotor treatment for a symmetric top linear molecule dimer a case study of ch3f h2
    2018
    Co-Authors: Xiaolong Zhang, Yu Zhai
    Abstract:

    A first effective six-dimensional ab initio Potential energy surface (PES) for CH3F–H2 which explicitly includes the intramolecular Q3 stretching normal mode of the CH3F monomer is presented. The electronic structure computations have been carried out at the explicitly correlated coupled cluster level of theory [CCSD(T)-F12a] with an augmented correlation-consistent triple zeta basis set. Five-dimensional analytical intermolecular PESs for ν3(CH3F) = 0 and 1 are then obtained by fitting the vibrationally averaged Potentials to the Morse/Long-Range (MLR) Potential function form. The MLR function form is applied to the nonlinear molecule-linear molecule case for the first time. These fits to 25 015 points have root-mean-square deviations of 0.74 cm−1 and 0.082 cm−1 for interaction energies less than 0.0 cm−1. Using the adiabatic hindered-rotor approximation, three-dimensional PESs for CH3F–paraH2 are generated from the 5D PESs over all possible orientations of the hydrogen monomer. The infrared and microwave spectra for CH3F–paraH2 dimer are predicted for the first time. These analytic PESs can be used for modeling the dynamical behavior in CH3F–(H2)N clusters, including the possible appearance of microscopic superfluidity.

  • intermolecular configurations dominated by quadrupole quadrupole electrostatic interactions explicit correlation treatment of the five dimensional Potential energy surface and infrared spectra for the co n2 complex
    2018
    Co-Authors: Jingmin Liu, Yu Zhai, Xiaolong Zhang
    Abstract:

    A thorough understanding of the intermolecular configurations of van der Waals complexes is a great challenge due to their weak interactions, floppiness and anharmonic nature. Although high-resolution microwave or infrared spectroscopy provides one of the most direct and precise pieces of experimental evidence, the origin and key role in determining such intermolecular configurations of a van der Waals system strongly depend on its highly accurate Potential energy surface (PES) and a detailed analysis of its ro-vibrational wavefunctions. Here, a new five-dimensional Potential energy surface for the van der Waals complex of CO–N2 which explicitly incorporates the dependence on the stretch coordinate of the CO monomer is generated using the explicitly correlated couple cluster (CCSD(T)-F12) method in conjunction with a large basis set. Analytic four-dimensional PESs are obtained by the least-squares fitting of vibrationally averaged interaction energies for v = 0 and v = 1 to the Morse/Long-Range Potential mode (VMLR). These fits to 7966 points have root-mean-square deviations (RMSD) of 0.131 cm−1 and 0.129 cm−1 for v = 0 and v = 1, respectively, with only 315 parameters. Energy decomposition analysis is carried out, and it reveals that the dominant factor in controlling intermolecular configurations is quadrupole–quadrupole electrostatic interactions. Moreover, the rovibrational levels and wave functions are obtained for the first time. The predicted infrared transitions and intensities for the ortho-N2–CO complex as well as the calculated energy levels for para-N2–CO are in good agreement with the available experimental data with RMSD discrepancies smaller than 0.068 cm−1. The calculated infrared band origin shift associated with the fundamental band frequency of CO is −0.721 cm−1 for ortho-N2–CO which is in excellent agreement with the experimental value of −0.739 cm−1. The agreement with experimental values validates the high quality of the PESs and enhances our confidence to explain the observed mystery lines around 2163 cm−1.

Feng Xie - One of the best experts on this subject based on the ideXlab platform.

Robert Le J Roy - One of the best experts on this subject based on the ideXlab platform.

  • analytic morse long range Potential energy surfaces and predicted infrared spectra for co h2 dimer and frequency shifts of co in para h2 n n 1 20 clusters
    2013
    Co-Authors: Xiaolong Zhang, Robert Le J Roy, Pierrenicholas Roy
    Abstract:

    A five-dimensional ab initio Potential energy surface (PES) for CO–H2 that explicitly incorporates dependence on the stretch coordinate of the CO monomer has been calculated. Analytic four-dimensional PESs are obtained by least-squares fitting vibrationally averaged interaction energies for  vCO = 0  and 1 to the Morse/Long-Range Potential function form. These fits to 30 206 points have root-mean-square (RMS) deviations of 0.087 and 0.082 cm−1, and require only 196 parameters. The resulting vibrationally averaged PESs provide good representations of the experimental infrared data: for infrared transitions of para H2–CO and ortho H2–CO, the RMS discrepancies are only 0.007 and 0.023 cm−1, which are almost in the same accuracy as those values of 0.010 and 0.018 cm−1 obtained from full six-dimensional ab initio PESs of V12 [P. Jankowski, A. R. W. McKellar, and K. Szalewicz, Science 336, 1147 (2012)]. The calculated infrared band origin shift associated with the fundamental of CO is −0.179 cm−1 for para H2–CO...

  • analytic morse long range Potential energy surfaces and predicted infrared spectra for co2 h2
    2010
    Co-Authors: Pierrenicholas Roy, Robert Le J Roy
    Abstract:

    Five-dimensional ab initio Potential energy surfaces (PESs) for CO2–H2 that explicitly incorporate dependence on the Q3 asymmetric-stretch normal-mode coordinate of the CO2 monomer and are parametrically dependent on its Q1 symmetric-stretch coordinate have been calculated. Analytic four-dimensional PESs are obtained by least-squares fitting vibrationally averaged interaction energies for v3(CO2)=0, and 1 to the Morse/Long-Range Potential function form. These fits to 23 113 points have root-mean-square (rms) deviations of 0.143 and 0.136 cm−1, and require only 167 parameters. The resulting vibrationally averaged PESs provide good representations of the experimental infrared data: for infrared transitions of para- and ortho-H2–CO2, the rms discrepancies are only 0.004 and 0.005 cm−1, respectively. The calculated infrared band origin shifts associated with the ν3 fundamental of CO2 are −0.179 and −0.092 cm−1 for para-H2–CO2 and ortho-H2–CO2, in good agreement with the (extrapolated) experimental values of −...

  • merging of the spline pointwise and morse long range Potential function forms for direct Potential fit data analyses
    2010
    Co-Authors: Jason Tao, Robert Le J Roy, A Pashov
    Abstract:

    Author Institution: Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada; Department of Physics, Sofia University, 5 James Bourcheier blvd, 1164 Sofia, Bulgaria

  • incorporating damping functions into the morse long range Potential function form improves both long range and very short range behaviour
    2010
    Co-Authors: Robert Le J Roy, Carl C Haugen, Jason Tao
    Abstract:

    Author Institution: Department of Chemistry, University of Waterloo, Waterloo, Ontario; N2L 3G1, Canada

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