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 N₂O₄ (Dinitrogen tetroxide)

BLYP/3-21G

Frequency in cm^-1

	Calculated			Experimental
Mode Number	Symmetry	Frequency	diff	Symmetry	Frequency	Comment
1	Ag	1156	-227	Ag	1383
2	Ag	735	-72	Ag	807
3	Ag	268	3	Ag	265
4	Au	97	15	Au	82
5	B1u	1012	-250	B1u	1261
6	B1u	646	-109	B1u	755
7	B2g	543	-114	B2g	657
8	B2u	1397	-360	B2u	1757
9	B2u	142	-123	B2u	265
10	B3g	1386	-332	B3g	1718
11	B3g	406	-74	B3g	480
12	B3u	342	-83	B3u	425	nu5 and nu8 switched from earlier work, such as 1983nou/che:1113

The calculated vibrational frequencies were scaled by 0.9945

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.