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Angela K Wilson - One of the best experts on this subject based on the ideXlab platform.
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vibrational Frequency Scale factors for density functional theory and the polarization consistent basis sets
Journal of Computational Chemistry, 2012Co-Authors: Marie L Laury, Matthew J Carlson, Angela K WilsonAbstract:Calculated harmonic vibrational frequencies systematically deviate from experimental vibrational frequencies. The observed deviation can be corrected by applying a Scale factor. Scale factors for: (i) harmonic vibrational frequencies [categorized into low ( 1000 cm−1)], (ii) vibrational contributions to enthalpy and entropy, and (iii) zero-point vibrational energies (ZPVEs) have been determined for widely used density functionals in combination with polarization consistent basis sets (pc-n, n = 0,1,2,3,4). The density functionals include pure functionals (BP86, BPW91, BLYP, HCTH93, PBEPBE), hybrid functionals with Hartree-Fock exchange (B3LYP, B3P86, B3PW91, PBE1PBE, mPW1K, BH&HLYP), hybrid meta functionals with the kinetic energy density gradient (M05, M06, M05-2X, M06-2X), a double hybrid functional with Moller-Plesset correlation (B2GP-PLYP), and a dispersion corrected functional (B97-D). The experimental frequencies for calibration were from 41 organic molecules and the ZPVEs for comparison were from 24 small molecules (diatomics, triatomics). For this family of basis sets, the Scale factors for each property are more dependent on the functional selection than on basis set level, and thus allow for a suggested Scale factor for each density functional when employing polarization consistent basis sets (pc-n, n = 1,2,3,4). A separate Scale factor is recommended when the un-polarized basis set, pc-0, is used in combination with the density functionals. © 2012 Wiley Periodicals, Inc.
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vibrational Frequency Scale factors for density functional theory and the polarization consistent basis sets
Journal of Computational Chemistry, 2012Co-Authors: Marie L Laury, Matthew J Carlson, Angela K WilsonAbstract:Calculated harmonic vibrational frequencies systematically deviate from experimental vibrational frequencies. The observed deviation can be corrected by applying a Scale factor. Scale factors for: (i) harmonic vibrational frequencies [categorized into low ( 1000 cm(-1))], (ii) vibrational contributions to enthalpy and entropy, and (iii) zero-point vibrational energies (ZPVEs) have been determined for widely used density functionals in combination with polarization consistent basis sets (pc-n, n = 0,1,2,3,4). The density functionals include pure functionals (BP86, BPW91, BLYP, HCTH93, PBEPBE), hybrid functionals with Hartree-Fock exchange (B3LYP, B3P86, B3PW91, PBE1PBE, mPW1K, BH&HLYP), hybrid meta functionals with the kinetic energy density gradient (M05, M06, M05-2X, M06-2X), a double hybrid functional with Moller-Plesset correlation (B2GP-PLYP), and a dispersion corrected functional (B97-D). The experimental frequencies for calibration were from 41 organic molecules and the ZPVEs for comparison were from 24 small molecules (diatomics, triatomics). For this family of basis sets, the Scale factors for each property are more dependent on the functional selection than on basis set level, and thus allow for a suggested Scale factor for each density functional when employing polarization consistent basis sets (pc-n, n = 1,2,3,4). A separate Scale factor is recommended when the un-polarized basis set, pc-0, is used in combination with the density functionals.
Thienphu Le - One of the best experts on this subject based on the ideXlab platform.
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use of the morlet mother wavelet in the Frequency Scale domain decomposition technique for the modal identification of ambient vibration responses
Mechanical Systems and Signal Processing, 2017Co-Authors: Thienphu LeAbstract:Abstract The Frequency-Scale domain decomposition technique has recently been proposed for operational modal analysis. The technique is based on the Cauchy mother wavelet. In this paper, the approach is extended to the Morlet mother wavelet, which is very popular in signal processing due to its superior time-Frequency localization. Based on the regressive form and an appropriate norm of the Morlet mother wavelet, the continuous wavelet transform of the power spectral density of ambient responses enables modes in the Frequency-Scale domain to be highlighted. Analytical developments first demonstrate the link between modal parameters and the local maxima of the continuous wavelet transform modulus. The link formula is then used as the foundation of the proposed modal identification method. Its practical procedure, combined with the singular value decomposition algorithm, is presented step by step. The proposition is finally verified using numerical examples and a laboratory test.
Patricia Mills - One of the best experts on this subject based on the ideXlab platform.
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prevalence and effect of problematic spasticity after traumatic spinal cord injury
Archives of Physical Medicine and Rehabilitation, 2017Co-Authors: Kaila A Holtz, Rachel Lipson, Vanessa K Noonan, Brian K Kwon, Patricia MillsAbstract:Abstract Objective To evaluate the prevalence and effect of spasticity after traumatic spinal cord injury (SCI). Design Prospective cohort study of the Rick Hansen Spinal Cord Injury Registry (RHSCIR) and retrospective review of inpatient medical charts. Setting Quaternary trauma center, rehabilitation center, and community settings. Participants Individuals (N=860) with a traumatic SCI between March 1, 2005, and March 31, 2014, prospectively enrolled in the Vancouver site RHSCIR were eligible for inclusion. Interventions Not applicable. Main Outcome Measures Questionnaires (Penn Spasm Frequency Scale, Spinal Cord Injury Health Questionnaire) and antispasticity medication use. Results In 465 patients, the prevalence of spasticity at community discharge was 65%, and the prevalence of problematic spasticity (defined as discharged on antispasticity medication) was 35%. Problematic spasticity was associated with cervicothoracic neurologic level and injury severity ( P Conclusions Spasticity is a highly prevalent secondary consequence of SCI, particularly in patients with severe motor incomplete cervicothoracic injuries. It is problematic in one third of all patients with SCI up to 5 years postinjury. One in 5 patients will have ongoing functional limitations related to spasticity, highlighting the importance of close community follow-up and the need for further research into spasticity management strategies.
Marie L Laury - One of the best experts on this subject based on the ideXlab platform.
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vibrational Frequency Scale factors for density functional theory and the polarization consistent basis sets
Journal of Computational Chemistry, 2012Co-Authors: Marie L Laury, Matthew J Carlson, Angela K WilsonAbstract:Calculated harmonic vibrational frequencies systematically deviate from experimental vibrational frequencies. The observed deviation can be corrected by applying a Scale factor. Scale factors for: (i) harmonic vibrational frequencies [categorized into low ( 1000 cm−1)], (ii) vibrational contributions to enthalpy and entropy, and (iii) zero-point vibrational energies (ZPVEs) have been determined for widely used density functionals in combination with polarization consistent basis sets (pc-n, n = 0,1,2,3,4). The density functionals include pure functionals (BP86, BPW91, BLYP, HCTH93, PBEPBE), hybrid functionals with Hartree-Fock exchange (B3LYP, B3P86, B3PW91, PBE1PBE, mPW1K, BH&HLYP), hybrid meta functionals with the kinetic energy density gradient (M05, M06, M05-2X, M06-2X), a double hybrid functional with Moller-Plesset correlation (B2GP-PLYP), and a dispersion corrected functional (B97-D). The experimental frequencies for calibration were from 41 organic molecules and the ZPVEs for comparison were from 24 small molecules (diatomics, triatomics). For this family of basis sets, the Scale factors for each property are more dependent on the functional selection than on basis set level, and thus allow for a suggested Scale factor for each density functional when employing polarization consistent basis sets (pc-n, n = 1,2,3,4). A separate Scale factor is recommended when the un-polarized basis set, pc-0, is used in combination with the density functionals. © 2012 Wiley Periodicals, Inc.
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vibrational Frequency Scale factors for density functional theory and the polarization consistent basis sets
Journal of Computational Chemistry, 2012Co-Authors: Marie L Laury, Matthew J Carlson, Angela K WilsonAbstract:Calculated harmonic vibrational frequencies systematically deviate from experimental vibrational frequencies. The observed deviation can be corrected by applying a Scale factor. Scale factors for: (i) harmonic vibrational frequencies [categorized into low ( 1000 cm(-1))], (ii) vibrational contributions to enthalpy and entropy, and (iii) zero-point vibrational energies (ZPVEs) have been determined for widely used density functionals in combination with polarization consistent basis sets (pc-n, n = 0,1,2,3,4). The density functionals include pure functionals (BP86, BPW91, BLYP, HCTH93, PBEPBE), hybrid functionals with Hartree-Fock exchange (B3LYP, B3P86, B3PW91, PBE1PBE, mPW1K, BH&HLYP), hybrid meta functionals with the kinetic energy density gradient (M05, M06, M05-2X, M06-2X), a double hybrid functional with Moller-Plesset correlation (B2GP-PLYP), and a dispersion corrected functional (B97-D). The experimental frequencies for calibration were from 41 organic molecules and the ZPVEs for comparison were from 24 small molecules (diatomics, triatomics). For this family of basis sets, the Scale factors for each property are more dependent on the functional selection than on basis set level, and thus allow for a suggested Scale factor for each density functional when employing polarization consistent basis sets (pc-n, n = 1,2,3,4). A separate Scale factor is recommended when the un-polarized basis set, pc-0, is used in combination with the density functionals.
Damian Moran - One of the best experts on this subject based on the ideXlab platform.
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An Evaluation of Harmonic Vibrational Frequency Scale Factors
The journal of physical chemistry. A, 2007Co-Authors: Jeffrey P. Merrick, Damian MoranAbstract:Scale factors for obtaining fundamental vibrational frequencies, low-Frequency vibrational frequencies, zeropoint vibrational energies (ZPVEs), and thermal contributions to enthalpy and entropy have been derived through a least-squares approach from harmonic frequencies determined at more than 100 levels of theory. Wave function procedures (HF, MP2, QCISD, QCISD(T), CCSD, and CCSD(T)) and a large and representative range of density functional theory (DFT) approaches (B3-LYP, BMK, EDF2, M05-2X, MPWB1K, O3-LYP, PBE, TPSS, etc.) have been examined in conjunction with basis sets such as 6-31G(d), 6-31+G(d,p), 6-31G(2df,p), 6-311+G(d,p), and 6-311+G(2df,p). The vibrational Frequency Scale factors were determined by a comparison of theoretical harmonic frequencies with the corresponding experimental fundamentals utilizing a standard set of 1066 individual vibrations. ZPVE Scale factors were generally obtained from a comparison of the computed ZPVEs with experimental ZPVEs for a smaller standard set of 39 molecules, though the effect of expansion to a 48 molecule data set was also examined. In addition to evaluating the Scale factors for a wide range of levels of theory, we have also probed the effect on Scale factors of varying the percentage of incorporated exact exchange in hybrid DFT calculations using a modified B3-LYP functional. This has revealed a near-linear relationship between the magnitude of the Scale factor and the proportion of exact exchange. Finally, we have investigated the effect of basis set size on HF, MP2, B3-LYP, and BMK Scale factors by deriving values with basis sets ranging from 6-31G(d) up to 6-311++G(3df,3pd) as well as with basis sets in the cc-pVnZ and aug-cc-pVnZ series and with the TZV2P basis.
