IV.D.6. (XII.D.1.) (XVIII.A.1.)

Bad calculated geometries

This page lists species for which the calculated geometry differs significantly from the experimental geometry. The comparison is made using the products of the moments of inertia (PMI). If the ratio of the experimental PMI to the calculated PMI is greater than 2 or less than 0.5 the molecule is displayed in the following table. These ratios can be changed with the form at the bottom of the table. Several small basis set have been left out. If you would like to see the comparison with all of the basis sets check the button in the form at the bottom of the table. The point group of the molecule is also listed.

Why is the geometry bad? Several simple reasons are:

linear versus bent geometry (note the change in point group: C_∞v and D_∞h are linear)
second row elements (such as Al through Cl and heavier) may need d functions for a good calculated geometry

The PMI values are displayed in amu Å² (for linear molecules) or amu³ Å⁶ for non-linear molecules.

Species	Name	PMI			point group		method/basis
Species	Name	Experiment	Theory	Ratio	Experiment	Theory	method/basis
C₄H₂	Diacetylene	115.1	26.0	0.23	D_∞h	C_2h	MP2FU/6-311G*
			299.0	2.60	D_∞h	C_2h	MP2FC/aug-cc-pVDZ
			55.9	0.49	D_∞h	C_2h	QCISD/6-311G*
			44.3	0.38	D_∞h	C_2h	CCD/6-311G*
			5.7	0.05	D_∞h	C_2h	B3LYP/aug-cc-pVDZ
			47.4	0.41	D_∞h	C_2h	BLYP/aug-cc-pVDZ
			22.2	0.19	D_∞h	C_2h	LSDA/aug-cc-pVDZ
			1.4	0.01	D_∞h	C_2h	PBEPBE/aug-cc-pVDZ
C₃O₂	Carbon suboxide	230.3	229060.3	994.77	D_∞h	C_2v	HF/cc-pVDZ
			216855.0	941.77	D_∞h	C_2v	HF/cc-pVTZ
			230929.9	1002.89	D_∞h	C_2v	HF/6-311+G(3df,2p)
			265276.4	1152.05	D_∞h	C_2v	HF/aug-cc-pVDZ
			230056.7	999.10	D_∞h	C_2v	HF/aug-cc-pVTZ
			193535.2	840.49	D_∞h	C_2v	HF/6-31G(2df,p)
			30639.2	133.06	D_∞h	C_2v	HF/6-311G**
			57836.3	251.17	D_∞h	C_2v	QCISD/6-311G**
			25291.0	109.83	D_∞h	C_2v	B3LYP/aug-cc-pVDZ
			99455.3	431.92	D_∞h	C_2v	CCSD(T)/cc-pVTZ
			1266.9	5.50	D_∞h	C_2v	BLYP/aug-cc-pVDZ
			14911.6	64.76	D_∞h	C_2v	B3PW91/aug-cc-pVDZ
			28288.5	122.85	D_∞h	C_2v	mPW1PW91/aug-cc-pVDZ
			31465.3	136.65	D_∞h	C_2v	B1B95/aug-cc-pVDZ
			219064.9	951.36	D_∞h	C_2v	MP3/6-31G*
Species	Name	PMI			point group		method/basis
Species	Name	Experiment	Theory	Ratio	Experiment	Theory	method/basis
NaOH	sodium hydroxide	39.5	889.1	22.51	C_∞v	C_s	B3LYP/6-31G*
			872.0	22.07	C_∞v	C_s	B3LYP/6-31G**
			398.4	10.09	C_∞v	C_s	B3LYP/6-311G*
			142.2	3.60	C_∞v	C_s	B3LYP/6-311G**
			1157.1	29.29	C_∞v	C_s	BLYP/6-31G*
			1156.3	29.27	C_∞v	C_s	BLYP/6-31G**
			921.3	23.32	C_∞v	C_s	BLYP/6-311G*
			644.8	16.32	C_∞v	C_s	BLYP/aug-cc-pVDZ
			879.8	22.27	C_∞v	C_s	BLYP/6-31G(2df,p)
			1002.7	25.38	C_∞v	C_s	BLYP/6-311G**
			736.0	18.63	C_∞v	C_s	B3PW91/6-31G*
			725.4	18.36	C_∞v	C_s	B3PW91/6-31G**
			672.7	17.03	C_∞v	C_s	mPW1PW91/6-31G*
			922.3	23.35	C_∞v	C_s	LSDA/6-31G*
			919.2	23.27	C_∞v	C_s	LSDA/6-31G**
			274.1	6.94	C_∞v	C_s	LSDA/cc-pVDZ
			274.6	6.95	C_∞v	C_s	LSDA/cc-pVTZ
			547.1	13.85	C_∞v	C_s	LSDA/6-311G*
			441.5	11.17	C_∞v	C_s	LSDA/6-31G(2df,p)
			597.1	15.11	C_∞v	C_s	LSDA/6-311G**
			664.1	16.81	C_∞v	C_s	B1B95/6-31G*
			718.2	18.18	C_∞v	C_s	B1B95/6-31G**
			1123.6	28.44	C_∞v	C_s	PBEPBE/6-31G*
			1112.2	28.15	C_∞v	C_s	PBEPBE/6-31G**
			851.2	21.55	C_∞v	C_s	PBEPBE/cc-pVDZ
			846.1	21.42	C_∞v	C_s	PBEPBE/cc-pVTZ
			851.0	21.54	C_∞v	C_s	PBEPBE/6-311G*
			603.9	15.29	C_∞v	C_s	PBEPBE/aug-cc-pVDZ
			879.7	22.27	C_∞v	C_s	PBEPBE/6-31G(2df,p)
			947.8	23.99	C_∞v	C_s	PBEPBE/6-311G**
			889.1	22.51	C_∞v	C_s	B3LYPultrafine/6-31G*
			1116.8	28.27	C_∞v	C_s	PBEPBEultrafine/6-31G*
Species	Name	PMI			point group		method/basis
Species	Name	Experiment	Theory	Ratio	Experiment	Theory	method/basis
C₂H	Ethynyl radical	11.6	2.6	0.22	C_∞v	C_s	LSDA/6-31G(2df,p)
			5.7	0.50	C_∞v	C_s	PBEPBE/6-311G**
NO₂	Nitrogen dioxide	3364.3	46.3	0.01	C_2v	D_∞h	SVWN/6-31+G**
C₃	carbon trimer	39.2	2894.5	73.93	D_∞h	C_2v	HF/aug-cc-pVDZ
			97.8	2.50	D_∞h	C_2v	MP2FU/aug-cc-pVDZ
			416.7	10.64	D_∞h	C_2v	QCISD/6-31+G**
			400.4	10.23	D_∞h	C_2v	B3LYP/aug-cc-pVDZ
			300.6	7.68	D_∞h	C_2v	QCISD(T)/6-31+G**
			202.1	5.16	D_∞h	C_2v	CCSD/6-31+G**
			233.4	5.96	D_∞h	C_2v	CCSD(T)/6-31+G**
			699.0	17.85	D_∞h	C_2v	BLYP/aug-cc-pVDZ
			973.0	24.85	D_∞h	C_2v	B3PW91/aug-cc-pVDZ
			895.9	22.88	D_∞h	C_2v	B3PW91/6-31G(2df,p)
			931.1	23.78	D_∞h	C_2v	mPW1PW91/aug-cc-pVDZ
			1956.4	49.97	D_∞h	C_2v	LSDA/cc-pVTZ
			1722.5	43.99	D_∞h	C_2v	LSDA/6-311G*
			1939.7	49.54	D_∞h	C_2v	LSDA/aug-cc-pVDZ
			1722.5	43.99	D_∞h	C_2v	LSDA/6-311G**
			933.5	23.84	D_∞h	C_2v	B1B95/aug-cc-pVDZ
			521.7	13.32	D_∞h	C_2v	PBEPBE/cc-pVTZ
			1100.8	28.12	D_∞h	C_2v	PBEPBE/6-311G*
			1067.2	27.26	D_∞h	C_s	PBEPBE/6-311+G(3df,2p)
			1669.5	42.64	D_∞h	C_2v	PBEPBE/aug-cc-pVDZ
			1115.5	28.49	D_∞h	C_2v	PBEPBE/aug-cc-pVTZ
			1460.4	37.30	D_∞h	C_2v	PBEPBE/6-311G**
Species	Name	PMI			point group		method/basis
Species	Name	Experiment	Theory	Ratio	Experiment	Theory	method/basis
MgOH	magnesium hydroxide	33.6	387.1	11.52	C_∞v	C_s	MP2FU/6-31G*
			178.1	5.30	C_∞v	C_s	MP2FU/aug-cc-pVDZ
			165.2	4.92	C_∞v	C_s	MP2FU/6-311G**
			420.2	12.50	C_∞v	C_s	MP2FC/6-31G*
			326.9	9.73	C_∞v	C_s	MP2FC/6-31G**
			312.4	9.30	C_∞v	C_s	MP2FC/cc-pVTZ
			137.0	4.07	C_∞v	C_s	MP2FC/6-311G*
			76.8	2.28	C_∞v	C_s	MP2FC/6-31G(2df,p)
			210.6	6.27	C_∞v	C_s	MP2FC/6-311G**
			466.1	13.87	C_∞v	C_s	MP4/6-31G*
			394.2	11.73	C_∞v	C_s	MP4/cc-pVTZ
			196.4	5.84	C_∞v	C_s	MP4/6-311G*
			427.3	12.71	C_∞v	C_s	QCISD/6-31G*
			256.1	7.62	C_∞v	C_s	QCISD/cc-pVTZ
			109.9	3.27	C_∞v	C_s	QCISD/6-311G*
			336.8	10.02	C_∞v	C_s	CCD/6-31G*
			16.8	0.50	C_∞v	C_s	CCD/6-311G*
			630.8	18.77	C_∞v	C_s	B3LYP/6-31G*
			578.8	17.22	C_∞v	C_s	B3LYP/6-31G**
			367.2	10.93	C_∞v	C_s	B3LYP/6-31+G**
			461.5	13.73	C_∞v	C_s	B3LYP/cc-pVDZ
			378.5	11.26	C_∞v	C_s	B3LYP/6-311G*
			267.8	7.97	C_∞v	C_s	B3LYP/aug-cc-pVTZ
			266.9	7.94	C_∞v	C_s	B3LYP/6-31G(2df,p)
			400.6	11.92	C_∞v	C_s	B3LYP/6-311G**
			476.6	14.18	C_∞v	C_s	QCISD(T)/6-31G*
			182.1	5.42	C_∞v	C_s	QCISD(T)/6-311G*
			402.5	11.98	C_∞v	C_s	CCSD/6-31G*
			75.0	2.23	C_∞v	C_s	CCSD/6-311G*
			466.8	13.89	C_∞v	C_s	CCSD(T)/6-31G*
			363.9	10.83	C_∞v	C_s	CCSD(T)/6-31G**
			340.2	10.12	C_∞v	C_s	CCSD(T)/cc-pVTZ
			167.8	4.99	C_∞v	C_s	CCSD(T)/6-311G*
			780.7	23.23	C_∞v	C_s	BLYP/6-31G*
			745.5	22.18	C_∞v	C_s	BLYP/6-31G**
			592.2	17.62	C_∞v	C_s	BLYP/6-31+G**
			615.2	18.30	C_∞v	C_s	BLYP/6-311G*
			534.1	15.89	C_∞v	C_s	BLYP/aug-cc-pVDZ
			591.2	17.59	C_∞v	C_s	BLYP/6-31G(2df,p)
			652.9	19.43	C_∞v	C_s	BLYP/6-311G**
			291.8	8.68	C_∞v	C_s	CID/6-31G*
			335.1	9.97	C_∞v	C_s	CISD/6-31G*
			573.1	17.05	C_∞v	C_s	B3PW91/6-31G*
			517.5	15.40	C_∞v	C_s	B3PW91/6-31G**
			311.5	9.27	C_∞v	C_s	B3PW91/6-31+G**
			292.7	8.71	C_∞v	C_s	B3PW91/6-311G*
			321.1	9.55	C_∞v	C_s	B3PW91/aug-cc-pVDZ
			302.8	9.01	C_∞v	C_s	B3PW91/6-311G**
			558.5	16.62	C_∞v	C_s	mPW1PW91/6-31G*
			499.0	14.85	C_∞v	C_s	mPW1PW91/6-31G**
			288.8	8.59	C_∞v	C_s	mPW1PW91/6-31+G**
			363.2	10.81	C_∞v	C_s	mPW1PW91/cc-pVTZ
			257.8	7.67	C_∞v	C_s	mPW1PW91/6-311G*
			309.2	9.20	C_∞v	C_s	mPW1PW91/aug-cc-pVDZ
			326.1	9.70	C_∞v	C_s	mPW1PW91/6-31G(2df,p)
			254.5	7.57	C_∞v	C_s	mPW1PW91/6-311G**
			646.3	19.23	C_∞v	C_s	LSDA/6-31G*
			612.0	18.21	C_∞v	C_s	LSDA/6-31G**
			393.6	11.71	C_∞v	C_s	LSDA/6-31+G**
			519.2	15.45	C_∞v	C_s	LSDA/cc-pVDZ
			424.3	12.62	C_∞v	C_s	LSDA/cc-pVTZ
			411.7	12.25	C_∞v	C_s	LSDA/6-311G*
			349.3	10.39	C_∞v	C_s	LSDA/aug-cc-pVDZ
			388.9	11.57	C_∞v	C_s	LSDA/6-31G(2df,p)
			430.6	12.81	C_∞v	C_s	LSDA/6-311G**
			646.2	19.23	C_∞v	C_s	SVWN/6-31G*
			522.7	15.55	C_∞v	C_s	B1B95/6-31G*
			481.6	14.33	C_∞v	C_s	B1B95/6-31G**
			253.7	7.55	C_∞v	C_s	B1B95/6-31+G**
			320.8	9.55	C_∞v	C_s	B1B95/cc-pVDZ
			275.4	8.19	C_∞v	C_s	B1B95/cc-pVTZ
			224.7	6.69	C_∞v	C_s	B1B95/6-311G*
			286.0	8.51	C_∞v	C_s	B1B95/6-31G(2df,p)
			206.9	6.16	C_∞v	C_s	B1B95/6-311G**
			568.3	16.91	C_∞v	C_s	B2PLYP/6-31G*
			270.7	8.06	C_∞v	C_s	B2PLYP/6-31+G**
			578.3	17.21	C_∞v	C_s	HSEh1PBE/6-31G*
			644.4	19.17	C_∞v	C_s	M06-2X/6-31G*
			773.1	23.00	C_∞v	C_s	PBEPBE/6-31G*
			738.2	21.96	C_∞v	C_s	PBEPBE/6-31G**
			579.5	17.24	C_∞v	C_s	PBEPBE/6-31+G**
			688.0	20.47	C_∞v	C_s	PBEPBE/cc-pVDZ
			619.6	18.44	C_∞v	C_s	PBEPBE/cc-pVTZ
			597.5	17.78	C_∞v	C_s	PBEPBE/6-311G*
			465.7	13.86	C_∞v	C_s	PBEPBE/6-311+G(3df,2p)
			559.2	16.64	C_∞v	C_s	PBEPBE/aug-cc-pVDZ
			611.1	18.18	C_∞v	C_s	PBEPBE/6-31G(2df,p)
			643.7	19.15	C_∞v	C_s	PBEPBE/6-311G**
			320.6	9.54	C_∞v	C_s	MP3/6-31G*
			630.8	18.77	C_∞v	C_s	B3LYPultrafine/6-31G*
			771.1	22.94	C_∞v	C_s	PBEPBEultrafine/6-31G*
Species	Name	PMI			point group		method/basis
Species	Name	Experiment	Theory	Ratio	Experiment	Theory	method/basis
MgF	Magnesium monofluoride	32.5	94.7	2.92	C_∞v	C_∞v	ROHF/6-311G**
FO₂	Dioxygen monofluoride	18541.2	104947.7	5.66	C_s	C_s	HF/cc-pVDZ
			112394.3	6.06	C_s	C_s	HF/6-311G*
			126851.9	6.84	C_s	C_s	HF/6-311+G(3df,2p)
			152950.8	8.25	C_s	C_s	HF/aug-cc-pVTZ
			117637.0	6.34	C_s	C_s	HF/6-311G**
			94653.9	5.11	C_s	C_s	MP2FU/6-311G**
			94807.8	5.11	C_s	C_s	MP2FC/6-311G**
			97539.5	5.26	C_s	C_s	MP4/cc-pVTZ
			46387.8	2.50	C_s	C_s	QCISD/6-311G*
			97822.2	5.28	C_s	C_s	MP3/6-31G*
Mg₂	Magnesium diatomic	181.5	76.4	0.42	D_∞h	D_∞h	HF/6-31G*
			76.4	0.42	D_∞h	D_∞h	HF/6-31G**
			76.7	0.42	D_∞h	D_∞h	HF/6-31+G**
			587.6	3.24	D_∞h	D_∞h	HF/6-311G*
			542.2	2.99	D_∞h	D_∞h	HF/6-311+G(3df,2p)
			76.0	0.42	D_∞h	D_∞h	HF/6-31G(2df,p)
			78.1	0.43	D_∞h	D_∞h	MP2FU/6-31+G**
			79.0	0.44	D_∞h	D_∞h	MP2FC/6-31G*
			79.0	0.44	D_∞h	D_∞h	MP2FC/6-31G**
			78.5	0.43	D_∞h	D_∞h	MP2FC/6-31G(2df,p)
			85.5	0.47	D_∞h	D_∞h	MP4/6-31G*
			80.7	0.44	D_∞h	D_∞h	QCISD/6-31G*
			79.5	0.44	D_∞h	D_∞h	CCD/6-31G*
			80.5	0.44	D_∞h	D_∞h	CCSD/6-31G*
			78.1	0.43	D_∞h	D_∞h	CISD/6-31G**
Species	Name	PMI			point group		method/basis
Species	Name	Experiment	Theory	Ratio	Experiment	Theory	method/basis
HCCO	ketenyl radical	885.2	1.4	0.00	C_s	C_s	HF/6-31G*
			45.9	0.05	C_s	C_∞v	HF/6-31G**
			41.4	0.05	C_s	C_s	HF/6-311G**
ONNO	NO dimer	193251.2	57752.3	0.30	C_2h	C_2h	HF/6-31G*
			58360.5	0.30	C_2h	C_2h	HF/cc-pVDZ
			56771.0	0.29	C_2h	C_2h	HF/cc-pVTZ
			56001.3	0.29	C_2h	C_2h	HF/6-311+G(3df,2p)
			57413.5	0.30	C_2h	C_2h	HF/aug-cc-pVDZ
			56748.7	0.29	C_2h	C_2h	HF/aug-cc-pVTZ
			56695.4	0.29	C_2h	C_2h	HF/6-31G(2df,p)
			56794.8	0.29	C_2h	C_2h	HF/6-311G**
			56088.6	0.29	C_2h	C_2h	HF/6-311+G(3df,2pd)
			81664.9	0.42	C_2h	C_2h	M06-2X/6-31G*

For descriptions of the methods (AM1, HF, MP2, ...) and basis sets (3-21G, 3-21G*, 6-31G, ...) see the glossary in section I.C. Predefined means the basis set used is determined by the method.

To change the selection ratio enter new values in the following form