National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 22May 2022
NIST Standard Reference Database 101
IIExperimental data
IIICalculated data
IVData comparisons
VCost comparisons
VIInput and output files
VIITutorials and Units
VIIILinks to other sites
XOlder CCCBDB versions
XIII Vibrations
XIVReaction data
XVEntropy data
XVIBibliographic data
XVIIIon data
XVIIIBad calculations
XIXIndex of properties
XXH-bond dimers

NIST policy on privacy, security, and accessibility.
© 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

return to home page

III.A.2.b. (XII.B.4.)

Calculated product of the moments of inertia

The moment of inertia is a measure of how much torque it takes to spin the molecule. The product of the three moments of inertia is used in the calculation of the molecular Entropy. This comparison of products of moments of inertia illustrates how well a given method/basis set performs at reproducing the experimental geometry. The three rotational constants (A,B,C for polyatomic species, only B for linear species) are inversely related to the moments of inertia (IA,IB,IC). See the section on the rotational contribution to the partition function in the thermochemistry page (Page I.D.) for more information.

Please enter the chemical formula

Rules for chemical formula

Species in the CCCBDB