National Institute of Standards and Technology

Computational Chemistry Comparison and Benchmark DataBase
Release 22	May 2022
NIST Standard Reference Database 101

I	Introduction
II	Experimental data
III	Calculated data
IV	Data comparisons
V	Cost comparisons
VI	Input and output files
VII	Tutorials and Units
VIII	Links to other sites
IX	Feedback
X	Older CCCBDB versions
XII	Geometries
XIII	Vibrations
XIV	Reaction data
XV	Entropy data
XVI	Bibliographic data
XVII	Ion data
XVIII	Bad calculations
XIX	Index of properties
XX	H-bond dimers
XXI	Oddities

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© 2013 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved.

The National Institute of Standards and Technology (NIST) is an agency of the U.S. Department of Commerce.

Please send questions, comments, corrections, additions and suggestions to cccbdb@nist.gov.

VII.

CCCBDB Units and Tutorials

A. Choose Units

1. Choose energy units
2. Choose polarizability units
3. Choose rotational constant units
4. Choose bond length units
5. Choose dipole and quadrupole units
6. Choose moment of inertia units

B. Unit Explanations

1. What's a hartree?
2. What's a cm^-1?
3. What's a Debye?

C. Explanations

1. Why scale vibrational frequencies?
2. Internal rotation of a methyl group
3. Calculating an Enthalpy of formation
4. Vertical versus adiabatic ionzation energies.
5. A glossary of computational terms.
6. A brief description of the thermochemical quantities and methods.
7. Two lectures on Extracting Thermochemical Information from ab Initio Data
   1. part 1
   2. part 2
8. Calculating one angle when another is known in a symmetric molecule
9. Contributions to entropy from different configurations
10. The number of constants needed to specify the dipole or quadrupole in various point groups.
11. Tutorial on Electric Quadrupole Moments (primitive, traceless, effective)
12. Vibrational Zero-Point Energy
13. Want other tutorials?

D. Forms for calculations and conversions

1. Form for calculating an enthalpy of formation using a reaction
2. Form for calculating the integrated heat capacity
3. Form for converting between moments of inertia and rotational constants
4. Perl script and information for computing ideal-gas thermodynamic functions from a Gaussian frequency calculation (From the NIST Chemical Informatics Research Group)

E. Reaction Suggestions

1. Isodesmic reaction product suggestions
You enter reactants and this page suggests products to form an isodesmic reaction.
2. Suggestions for species with well defined experimental enthalpies of formation
3. Binary decomposition search. Given "A" what are possible products "B" and "C" and their relative enthalpies.