Eckart Inertias

By Bryan M. Wong

University of California, Riverside



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Eckart Inertias: calculates effective Eckart inertias for large-amplitude torsions. The Eckart inertias are obtained by solving a system of transcendental equations using the Powell dogleg method. Since this system is highly nonlinear, analytical Jacobians have been implemented in the dogleg method to maximize computational efficiency.


This is a suite of MATLAB codes to calculate effective Eckart inertias for large amplitude torsions published by Bryan M. Wong, Ryan L. Thom, and Robert W. Field in The Journal of Physical Chemistry A 110, 7406 - 7413 (2006). The zip file includes some sample input files.


Prof. Bryan M. Wong is an assistant professor in the Department of Chemical & Environmental Engineering and Materials Science & Engineering Program at UC Riverside. He is listed in the Reviews in Computational Chemistry (Volume 27) as a researcher who "regularly publishes in journals that focus on computing at the molecular level." Prof. Wong received his Ph.D. in physical chemistry from the Massachusetts Institute of Technology (MIT) in 2007.


B. M. Wong, R. L. Thom, and R. W. Field, "Accurate Inertias for Large-Amplitude Motions: Improvements on Prevailing Approximations." Journal of Physical Chemistry A, 110, 7406 (2006).

B. M. Wong, A. H. Steeves, and R. W. Field, "Electronic Signatures of Large Amplitude Motions: Dipole Moments of Vibrationally Excited Local-Bend and Local-Stretch States of S0 Acetylene." Journal of Physical Chemistry B, 110, 18912 (2006)

B. M. Wong and S. Raman, "Thermodynamic Calculations for Molecules with Asymmetric Internal Rotors - Application to 1,3-Butadiene." Journal of Computational Chemistry, 28, 759 (2007).

B. M. Wong, M. M. Fadri, and S. Raman, "Thermodynamic Calculations for Molecules with Asymmetric Internal Rotors. II. Application to the 1,2-Dihaloethanes." Journal of Computational Chemistry, 29, 481 (2008)

H. A. Bechtel, A. H. Steeves, B. M. Wong, and R. W. Field, "Evolution of Chemical Bonding during HCN ↔ HNC Isomerization as Revealed Through Nuclear Quadrupole Hyperfine Structure." Angewandte Chemie International Edition, 47, 2969 (2008)

B. M. Wong, "Nuclear Quadrupole Hyperfine Structure in HC14N/H14NC and DC15N/D15NC Isomerization: A Diagnostic Tool for Characterizing Vibrational Localization." Physical Chemistry Chemical Physics, 10, 5599 (2008)

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Researchers should cite this work as follows:

  • Bryan M. Wong (2014), "Eckart Inertias,"

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