National Institute of Standards and Technology

Computational Chemistry Comparison and Benchmark DataBase
Release 19	April 2018
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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IV.C.1. (XIII.D.1.)

Compare vibrational frequencies in CCCBDB for CHBr (bromomethylene)

HF/3-21G

Frequency in cm^-1

	Calculated			Experimental
Mode Number	Symmetry	Frequency	diff	Symmetry	Frequency	Comment
1	A'	2807	-95	A'	2902	CH str
2	A'	1128	10	A'	1118	bend
3	A'	542	-134	A'	676	CBr str

The calculated vibrational frequencies were scaled by 0.9056

See section XIII.C.3 List or set vibrational scaling factors to change the scale factors used here.
See section III.B.3.c Calculate a vibrational scaling factor for a set of molecules to determine the least squares best scaling factor.
See section III.B.3.b List of vibrational scaling factors and their uncertainties for information on where the above scaling factor is from.