Quadratic Corrections to Harmonic Vibrational Frequencies Outperform Linear Models

Type of content
Journal Article
Thesis discipline
Degree name
Publisher
AMER CHEMICAL SOC
Journal Title
Journal ISSN
Volume Title
Language
English
Date
2015
Authors
Sibaev, Marat
Crittenden, Deborah
Abstract

Simulating accurate infrared spectra is a longstanding problem in computational quantum chemistry. Linearly scaling harmonic frequencies to better match experimental data is a popular way of approximating anharmonic effects while simultaneously attempting to account for deficiencies in ab initio method and/or basis set. As this approach is empirical, it is also nonvariational and unbounded, so it is important to separate and quantify errors as robustly as possible. Eliminating the confounding factor of methodological incompleteness enables us to explore the intrinsic accuracy of the scaling approach alone. We find that single-coefficient linear scaling methods systematically overcorrect low frequencies, while generally undercorrecting higher frequencies. A two-parameter polynomial model gives significantly better predictions without systematic bias in any spectral region, while a single-parameter quadratic scaling model is parameterized to minimize overcorrection errors while only slightly decreasing predictive power.

Description
Citation
Sibaev M, Crittenden DL (2015). Quadratic Corrections to Harmonic Vibrational Frequencies Outperform Linear Models. The Journal of Physical Chemistry A. 119(52). 13107-13112.
Keywords
Science & Technology, Physical Sciences, Chemistry, Physical, Physics, Atomic, Molecular & Chemical, Chemistry, Physics, GAUSSIAN-BASIS SETS, CORRELATED MOLECULAR CALCULATIONS, RELATIVISTIC EFFECTIVE POTENTIALS, DENSITY-FUNCTIONAL THEORY, CONSISTENT BASIS-SETS, SPIN-ORBIT OPERATORS, ZERO-POINT ENERGIES, SCALE FACTORS, FORCE-FIELDS, NONCOVALENT INTERACTIONS
Ngā upoko tukutuku/Māori subject headings
ANZSRC fields of research
0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics
0306 Physical Chemistry (incl. Structural)
0307 Theoretical and Computational Chemistry
Fields of Research::34 - Chemical sciences::3407 - Theoretical and computational chemistry::340701 - Computational chemistry
Fields of Research::34 - Chemical sciences::3407 - Theoretical and computational chemistry::340704 - Theoretical quantum chemistry
Fields of Research::34 - Chemical sciences::3401 - Analytical chemistry::340101 - Analytical spectrometry
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