Computational thermochemistry: Automated generation of scale factors for vibrational frequencies calculated by electronic structure model chemistries

Abstract We present a Python program, FREQ, for calculating the optimal scale factors for calculating harmonic vibrational frequencies, fundamental vibrational frequencies, and zero-point vibrational energies from electronic structure calculations. The program utilizes a previously published scale factor optimization model (Alecu et al., 2010) to efficiently obtain all three scale factors from a set of computed vibrational harmonic frequencies. In order to obtain the three scale factors, the user only needs to provide zero-point energies of 15 or 6 selected molecules. If the user has access to the Gaussian 09 or Gaussian 03 program, we provide the option for the user to run the program by entering the keywords for a certain method and basis set in the Gaussian 09 or Gaussian 03 program. Four other Python programs, input.py, input6, pbs.py, and pbs6.py, are also provided for generating Gaussian 09 or Gaussian 03 input and PBS files. The program can also be used with data from any other electronic structure package. A manual of how to use this program is included in the code package. Program summary Program title: FREQ Catalogue identifier: AFBH_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AFBH_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland at http://www.cpc.cs.qub.ac.uk or from Truhlar group software page at comp.chem.umn.edu/freq/ Licensing provisions: GNU GPL v3 No. of lines in distributed program, including test data, etc.: 3013 No. of bytes in distributed program, including test data, etc.: 212537 Distribution format: tar.gz Programming language: PYTHON. Computer: Any computer with PYTHON compiler. Operating systems: Linux, Unix. Classifications: 16.3, 23. External routines: Gaussian 03 or Gaussian 09 (see “Restrictions”). Nature of problem: Optimization of property-specific scale factors for vibrational frequencies for a specific electronic model chemistry. Solution method: The method is based on minimizing the root-mean-square deviation between a set of zero-point energies derived from harmonic vibrational frequencies (either provided by the user or computed on the fly) and their experimentally determined counterparts. Restrictions: In order to compute the electronic model chemistry’s harmonic zero-point energies on the fly, the user must have access to the Gaussian 03 or Gaussian 09 program. If the electronic model chemistry’s zero-point energies are read in, no other program is required. Additional comments: After opening the FREQ.tar.gz file, the user will find a run.sh file which can be used to run all the programs to obtain the scaling factors for a user-chosen electronic structure model chemistry. Running time: Less than a second if the user provides the zero-point energies; if zero-point energies are to be computed, the running time depends on the electronic model chemistry used to compute them as well as the efficiency of the Gaussian 09 program, in our test we obtain the results within 10 min by using one node with eight processors for each Gaussian 09 input on Minnesota Supercomputing Institute’s Mesabi supercomputer.

[1]  Curtis L. Janssen,et al.  Concerning zero‐point vibrational energy corrections to electronic energies , 1991 .

[2]  Parr,et al.  Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density. , 1988, Physical review. B, Condensed matter.

[3]  N. Handy,et al.  Extensions and tests of “multimode”: a code to obtain accurate vibration/rotation energies of many-mode molecules , 1998 .

[4]  D. Truhlar,et al.  Vibrational configuration interaction using a tiered multimode scheme and tests of approximate treatments of vibrational angular momentum coupling: a case study for methane. , 2013, The journal of physical chemistry. A.

[5]  K. Irikura.  Experimental Vibrational Zero-Point Energies: Diatomic Molecules , 2007 .

[6]  D. Truhlar,et al.  Prediction of experimentally unavailable product branching ratios for biofuel combustion: the role of anharmonicity in the reaction of isobutanol with OH. , 2014, Journal of the American Chemical Society.

[7]  Donald G Truhlar,et al.  Practical methods for including torsional anharmonicity in thermochemical calculations on complex molecules: the internal-coordinate multi-structural approximation. , 2011, Physical chemistry chemical physics : PCCP.

[8]  Yuri L. Volobuev,et al.  Convergence of variational calculations of the ground-state energy of HF dimer , 2000 .

[9]  Donald G Truhlar,et al.  Calculation of converged rovibrational energies and partition function for methane using vibrational-rotational configuration interaction. , 2004, The Journal of chemical physics.

[10]  A. D. Isaacson.  Removing resonance effects from quantum mechanical vibrational partition functions obtained from perturbation theory , 1998 .

[11]  Kenneth L. Clarkson,et al.  MSTor: A program for calculating partition functions, free energies, enthalpies, entropies, and heat capacities of complex molecules including torsional anharmonicity , 2012, Comput. Phys. Commun..

[12]  J. Tennyson,et al.  An effective computational approach to the calculation of the vibration-rotation spectra of triatomic molecules , 1988 .

[13]  A. Becke,et al.  Density-functional exchange-energy approximation with correct asymptotic behavior. , 1988, Physical review. A, General physics.

[14]  Jan M. L. Martin.  On the performance of large Gaussian basis sets for the computation of total atomization energies , 1992 .

[15]  Leo Radom,et al.  Harmonic Vibrational Frequencies: An Evaluation of Hartree−Fock, Møller−Plesset, Quadratic Configuration Interaction, Density Functional Theory, and Semiempirical Scale Factors , 1996 .

[16]  Dong H. Zhang,et al.  Photofragmentation of HF dimer: Quantum dynamics studies on ab initio potential energy surfaces , 1993 .

[17]  L. Radom,et al.  Scaling Factors for Obtaining Fundamental Vibrational Frequencies and Zero-Point Energies from HF/6–31G* and MP2/6–31G* Harmonic Frequencies , 1993 .

[18]  D. Truhlar,et al.  General method for removing resonance singularities in quantum mechanical perturbation theory , 1996 .

[19]  D. Truhlar,et al.  The M06 suite of density functionals for main group thermochemistry, thermochemical kinetics, noncovalent interactions, excited states, and transition elements: two new functionals and systematic testing of four M06-class functionals and 12 other functionals , 2008 .

[20]  Vincenzo Barone,et al.  Anharmonic vibrational properties by a fully automated second-order perturbative approach. , 2005, The Journal of chemical physics.

[21]  G. Scuseria,et al.  Gaussian 03, Revision E.01. , 2007 .

[22]  Donald G. Truhlar,et al.  MSTor version 2013: A new version of the computer code for the multi-structural torsional anharmonicity, now with a coupled torsional potential , 2013, Comput. Phys. Commun..

[23]  J. Pople,et al.  Self‐consistent molecular orbital methods. XX. A basis set for correlated wave functions , 1980 .

[24]  Jack G. Lauderdale,et al.  A vibrational configuration interaction program for energies and resonance widths , 1988 .

[25]  Donald G. Truhlar,et al.  Optimized Parameters for Scaling Correlation Energy , 1999 .

[26]  N. Handy,et al.  Variational calculation of vibration-rotation energy levels for triatomic molecules , 1975 .

[27]  A. D. McLean,et al.  Contracted Gaussian basis sets for molecular calculations. I. Second row atoms, Z=11–18 , 1980 .

[28]  M. Mladenović,et al.  Converging multidimensional rovibrational variational calculations: the dissociation energy of (HF)2 , 2000 .

[29]  P. N. Day,et al.  The accuracy of second order perturbation theory for multiply excited vibrational energy levels and partition functions for a symmetric top molecular ion , 1993 .

[30]  Giovanni Scalmani,et al.  Gaussian 09W, revision A. 02 , 2009 .

[31]  K. Rao,et al.  Molecular Spectroscopy: Modern Research , 1972 .