III.G.1.a.

Comparison of levels of theory for O-C

Click on an entry for a histogram of the values.
The subscript refers to how many bonds of that type have been calculated.

average calculated bond lengths (Å)

Methods with predefined basis sets
semi-empirical	AM1	1.3064 95
	PM3	1.3301 321
	PM6	1.3792 420
composite	G2	1.3432 329
	G3	1.3480 351
	G3B3	1.3387 328
	CBS-Q	1.3498 250
molecular mechanics	DREIDING	1.2635 3

average calculated bond lengths (Å)

Methods with standard basis sets
		STO-3G	3-21G	3-21G*	6-31G	6-31G*	6-31G**	6-31+G**	6-311G*	6-311G**	6-31G(2df,p)	6-311+G(3df,2p)	6-311+G(3df,2pd)	TZVP	cc-pVDZ	cc-pVTZ	cc-pVQZ	aug-cc-pVDZ	aug-cc-pVTZ	aug-cc-pVQZ	cc-pV(T+d)Z	cc-pCVDZ	cc-pCVTZ	Sadlej_pVTZ
hartree fock	HF	1.3709 355	1.3465 393	1.3495 365	1.3474 364	1.3068 403	1.3177 365	1.3341 379	1.3139 365	1.3155 356	1.3264 359	1.3129 272	1.2928 15	1.3440 428	1.3168 362	1.3125 356	1.2578 78	1.3184 351	1.3118 349	1.2494 46	1.1461 3	1.4011 2	1.3979 2	1.2535 12
hartree fock	ROHF	1.2797 18	1.3292 39	1.3302 39	1.3323 38	1.2906 44	1.3002 40	1.3005 40	1.2977 40	1.3063 35	1.2142 20			1.4098 2	1.2981 40	1.2943 40	1.2449 21	1.2711 32	1.2650 32	1.2296 20
density functional	LSDA	1.3726 377	1.3487 380	1.3485 384	1.3467 377	1.3204 373	1.3188 378	1.3222 374	1.3160 373	1.3149 375	1.3097 370			1.4200 2	1.3180 374	1.3153 371	1.2116 17	1.3198 361	1.2720 42	1.1982 16
	SVWN		1.3968 353			1.3730 348	1.4151 2	1.3758 352	1.4159 2	1.4172 2	1.4118 2				1.4135 2	1.4167 2		1.4234 2	1.4199 2
	BLYP	1.4257 354	1.3868 365	1.3724 273	1.3871 358	1.3606 356	1.3555 361	1.3602 357	1.3388 268	1.3538 351	1.3638 354			1.4622 2	1.3555 356	1.3520 354		1.3723 217
	B1B95	1.3801 352	1.3600 366	1.3607 364	1.3583 364	1.3308 349	1.3289 364	1.3357 372	1.3258 360	1.3268 358	1.3206 343			1.4244 2	1.3279 359	1.3243 356	1.2055 19	1.3221 329	1.2754 71	1.2067 18		1.4169 2	1.4148 2
	B3LYP	1.4031 360	1.3672 396	1.3716 366	1.3709 364	1.3378 386	1.3409 362	1.3409 390	1.3373 363	1.3248 148	1.3340 346	1.3669 209	1.3159 15	1.3645 427	1.3393 351	1.3374 349	1.2697 56	1.3109 208	1.3134 164	1.2707 46	1.1700 3	1.4298 2	1.4271 2	1.2772 12
	B3LYPultrafine	1.3720 3	1.3364 19			1.3348 340		1.3214 66				1.1986 1	1.3015 13						1.2983 14
	B3PW91	1.3780 147	1.3675 370	1.3681 367	1.3662 365	1.3303 356	1.3360 365	1.3260 273	1.3323 365	1.3183 145	1.3442 354			1.4287 2	1.3354 364	1.3321 362		1.3492 217
	mPW1PW91	1.3723 148	1.3642 360	1.3516 183	1.3634 360	1.3274 357	1.3327 360	1.3345 359	1.3289 360	1.3298 352	1.3410 354			1.4240 2	1.3307 353	1.3111 218		1.3442 243	1.3296 23
	M06-2X	1.5710 12	1.5564 12	1.5567 12	1.5498 12	1.3754 358	1.5208 12	1.5229 12	1.5187 12	1.5194 12	1.5169 12			1.4261 2	1.5195 12	1.5186 12		1.4928 8	1.4888 8
	PBEPBE	1.3923 150	1.3904 369	1.3589 155	1.3610 149	1.3541 362	1.3595 355	1.3608 367	1.3557 359	1.3455 352	1.3439 340	1.3757 214	1.5246 15	1.4440 2	1.3578 345	1.3558 353	1.2211 19	1.3231 39	1.3209 99	1.2032 18	1.1694 1			1.2854 12
	PBEPBEultrafine		1.3552 12			1.3712 259		1.3266 19					1.3190 12						1.3207 12
	HSEh1PBE	1.5791 12	1.5566 12	1.5570 12	1.5531 12	1.3800 349	1.5217 12	1.5240 12	1.5189 12	1.5199 12	1.5180 12			1.4256 2	1.5204 12	1.5189 12		1.4933 8	1.4887 8
Moller Plesset perturbation	MP2FC	1.3821 149	1.3824 394	1.3860 360	1.3900 359	1.3455 392	1.3454 362	1.3469 394	1.3351 345	1.3383 354	1.3305 243	1.2092 1	1.2778 14	1.3642 428	1.3420 362	1.3216 253	1.2968 16	1.3247 191	1.3142 73	1.3040 12	1.1810 3	1.2662 10	1.2576 6	1.2867 12
	MP2FU	1.3784 140	1.3638 222	1.3662 181	1.3713 179	1.3525 362	1.3317 261	1.3361 268	1.3354 354	1.3226 144	1.3208 143			1.3409 6	1.3234 222	1.3200 170	1.3032 12	1.3028 50	1.2780 37	1.3060 10	1.1778 3	1.2653 10	1.2554 6
	ROMP2	1.4257 25	1.4088 23	1.4091 23	1.4057 24	1.3648 24	1.3642 24	1.3840 22	1.3736 22	1.3551 24	1.3532 24			1.4407 1	1.3794 22	1.3726 22	1.1478 7	1.3202 22	1.2218 13	1.1914 10
	MP3					1.3394 339
	MP4	1.4217 7	1.3598 99	1.3394 5	1.3523 6	1.3330 142	1.2031 1	1.2040 1	1.2567 6	1.3212 71	1.3577 7					1.2829 41
	B2PLYP	1.5853 12	1.5691 12	1.5694 12	1.5690 12	1.3849 359	1.5314 12	1.3869 357	1.5278 12	1.5285 12	1.5354 11			1.4355 2	1.5297 12	1.5293 11		1.5013 8	1.4832 8
Configuration interaction	CID	1.3605 3	1.3553 153	1.3536 138	1.3566 137	1.3192 254	1.7606 2	1.7619 2	1.3147 147	1.2911 11	1.3319 7				1.1766 1	1.1678 1
Configuration interaction	CISD	1.3314 4	1.3573 158	1.3566 141	1.3584 139	1.3212 254	1.4374 7	1.1951 2	1.3146 142	1.2918 11	1.3377 6				1.7623 2	1.1696 1
Quadratic configuration interaction	QCISD	1.4525 35	1.3885 304	1.3647 150	1.3784 157	1.3379 229	1.3362 166	1.3348 170	1.3206 196	1.3208 161	1.3361 83			1.4315 2	1.3250 159	1.2967 73		1.3531 23	1.2864 16		1.1554 1
Quadratic configuration interaction	QCISD(T)		1.3170 8	1.3354 4	1.3296 4	1.3166 123	1.2591 5	1.3142 13	1.3473 13	1.3477 14	1.3125 3			1.4439 1	1.3048 62	1.3095 54		1.2454 31	1.2022 19
Coupled Cluster	CCD	1.4507 35	1.3664 165	1.3644 150	1.3695 159	1.3461 269	1.3235 155	1.3292 155	1.3178 158	1.3266 89	1.3295 86			1.4279 2	1.3208 155	1.2975 64		1.2782 47	1.2213 34			1.4256 2	1.4197 2
	CCSD		1.3072 8	1.3248 4	1.3206 4	1.3232 125	1.2525 5	1.3080 13	1.3299 13	1.4428 17	1.3053 3				1.3735 29	1.4187 26
	CCSD(T)		1.2685 17	1.3325 4	1.3270 4	1.3428 122	1.2856 22	1.2732 24	1.2562 15	1.2871 19	1.2533 5	1.2612 5	1.2936 4	1.4432 1	1.3113 71	1.2947 72	1.1940 7	1.2936 62	1.2475 31	1.1853 4	1.1622 1	1.2629 6	1.1684 4
	CCSD(T)=FULL					1.3331 49								1.4420 1	1.3737 26	1.3075 17	1.2013 4	1.3298 22	1.2142 11	1.1353 2		1.2620 6	1.2541 6

average calculated bond lengths (Å)

Methods with effective core potentials (select basis sets)
		CEP-31G	CEP-31G*	CEP-121G	CEP-121G*	LANL2DZ	SDD
hartree fock	HF	1.3592 361	1.3309 346	1.3576 361	1.3277 350	1.3530 362	1.3521 360
density functional	B1B95	1.3817 266	1.3510 264	1.2793 3	1.2528 3	1.2734 3	1.2734 3
	B3LYP	1.3868 361	1.3565 345	1.3845 357	1.3534 347	1.3771 359	1.3768 357
	B3LYPultrafine					1.2471 1
Moller Plesset perturbation	MP2FC	1.4080 361	1.3612 344	1.4025 356	1.3583 346	1.4002 364	1.4007 360

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.