III.G.1.a.

Comparison of levels of theory for N-O

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	1.1770 18
	PM3	1.2974 68
	PM6	1.2471 94
composite	G2	1.3190 70
	G3	1.2667 78
	G3B3	1.2503 80
	CBS-Q	1.2738 62

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)	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	1.3149 80	1.2884 79	1.2891 79	1.2532 77	1.2542 94	1.2691 87	1.2333 81	1.2628 87	1.2266 81	1.2280 76	1.2119 54	1.2289 84	1.2642 87	1.2664 82	1.2407 31	1.2307 75	1.2761 76	1.2575 24	1.1434 3	1.1529 3	1.1495 3	1.1554 4
hartree fock	ROHF	1.3233 16	1.2883 22	1.2890 22	1.2194 16	1.2452 25	1.2475 22	1.2518 22	1.2411 22	1.2541 19	1.2618 16	1.1129 1		1.2418 22	1.2425 22	1.2607 17	1.2535 19	1.2492 19	1.2604 17
density functional	LSDA	1.3418 86	1.3019 89	1.3020 89	1.2814 83	1.2458 83	1.2458 83	1.2453 83	1.2397 83	1.2398 83	1.2395 83		1.3535 2	1.2424 83	1.2378 83	1.1964 14	1.2386 79	1.2081 18	1.1957 14
	SVWN		1.3063 75			1.2664 71	1.3421 2	1.2628 75	1.3467 2	1.3467 2	1.3393 2			1.3447 2	1.3467 2
	BLYP	1.3709 75	1.3407 81	1.3288 70	1.3191 80	1.2863 81	1.2772 81	1.2759 80	1.2677 70	1.2733 78	1.2711 78		1.4165 2	1.2749 80	1.2709 81		1.3678 53
	B1B95	1.3359 79	1.3013 80	1.3015 80	1.2808 80	1.2422 80	1.2437 80	1.2434 80	1.2379 80	1.2380 80	1.2384 79		1.3337 2	1.2401 80	1.2351 80	1.2022 16	1.2362 75	1.2169 21	1.2054 15
	B3LYP	1.3987 86	1.3106 87	1.3111 87	1.2927 87	1.2940 91	1.2550 87	1.2552 87	1.2494 87	1.2387 38	1.2491 84	1.3407 49	1.2636 84	1.2517 87	1.2476 87	1.2320 24	1.2519 57	1.2299 47	1.2299 24	1.1664 3	1.1763 3	1.1700 3	1.1881 4
	B3LYPultrafine					1.2523 78		1.2453 25								1.3560 1
	B3PW91	1.3300 36	1.3018 81	1.3024 81	1.2823 81	1.2452 81	1.2463 80	1.2406 70	1.2392 81	1.2216 32	1.2397 78		1.3454 2	1.2416 81	1.2381 81		1.3278 53
	mPW1PW91	1.3263 36	1.2979 79	1.2950 43	1.2770 81	1.2411 79	1.2424 78	1.2407 79	1.2350 79	1.2346 81	1.2351 78		1.3344 2	1.2399 77	1.2260 59		1.3234 54	1.2704 4
	M06-2X	1.4052 2	1.3792 2	1.3838 2	1.3554 2	1.2427 78	1.3175 2	1.3178 2	1.3172 2	1.3172 2	1.3131 2		1.3203 2	1.3191 2	1.3159 2
	PBEPBE	1.3448 33	1.3228 81	1.3049 35	1.2850 35	1.2648 81	1.2648 81	1.2649 81	1.2598 81	1.2600 81	1.2804 78	1.3510 52	1.3924 2	1.2638 78	1.2587 81	1.2236 16	1.2599 6	1.2542 28	1.2201 16				1.1961 4
	PBEPBEultrafine					1.2691 53
	HSEh1PBE	1.4218 2	1.3887 2	1.3962 2	1.3723 2	1.2460 77	1.3278 2	1.3289 2	1.3290 2	1.3290 2	1.3242 2		1.3350 2	1.3307 2	1.3290 2
Moller Plesset perturbation	MP2FC	1.3493 34	1.3364 84	1.3368 84	1.3207 78	1.3077 90	1.2696 84	1.2699 77	1.2587 83	1.2534 78	1.2377 50		1.2731 84	1.2630 84	1.2493 57	1.2391 6	1.2463 48	1.2366 19	1.2295 5	1.1741 3	1.1743 4	1.1678 4	1.1905 4
	MP2FU	1.3517 33	1.3255 58	1.3338 42	1.3198 42	1.2649 78	1.2619 63	1.2652 66	1.2536 77	1.2442 28	1.2365 29		1.3850 2	1.2500 59	1.2467 39	1.2367 6	1.2400 22	1.2270 15	1.3396 2	1.1708 3	1.1738 4	1.1663 4
	ROMP2	1.4569 15	1.3464 13	1.3464 13	1.3141 13	1.2464 16	1.2464 16	1.2460 16	1.2199 13	1.2200 13	1.2225 10			1.2258 13	1.2057 10	1.1852 5	1.2209 13	1.2102 13	1.1933 7
	MP3					1.2473 76
	MP4	1.3808 3	1.4032 32	1.4420 3	1.4400 3	1.2740 49			1.2466 4	1.2659 25	1.2048 3				1.2536 34
	B2PLYP	1.4475 2	1.4265 2	1.4325 2	1.4251 2	1.2624 77	1.3593 2	1.2618 78	1.3580 2	1.3580 2	1.3526 2		1.3691 2	1.3625 2	1.3598 2
Configuration interaction	CID		1.3232 39	1.3329 31	1.2834 29	1.2445 65	1.2948 4	1.2950 4	1.2201 34	1.0851 1	1.1644 3			1.4246 1	1.4173 1
Configuration interaction	CISD		1.3419 41	1.3545 33	1.2833 30	1.2446 68	1.2962 4	1.4321 1	1.2241 30	1.0852 1	1.1653 3			1.2910 4	1.4197 1
Quadratic configuration interaction	QCISD	1.2926 4	1.3225 73	1.3530 30	1.3215 38	1.2539 65	1.2623 42	1.2528 49	1.2381 56	1.2428 54	1.2321 24		1.3366 2	1.2417 44	1.2291 37		1.2978 4	1.2854 4
	QCISD(T)					1.2514 35			1.1887 2	1.1885 3			1.3618 2	1.2651 22	1.2424 18		1.2509 15	1.2311 6
	QCISD(TQ)					1.1806 1												1.1611 1
Coupled Cluster	CCD	1.2847 4	1.3217 39	1.3348 30	1.3095 40	1.2497 76	1.2542 38	1.2554 41	1.2385 43	1.2249 30	1.2253 27		1.3237 2	1.2375 43	1.2426 28		1.2333 20	1.2399 13			1.1644 2	1.1563 2
	CCSD					1.2398 51			1.1784 2					1.2991 8	1.2894 8
	CCSD(T)		1.2203 4			1.2572 48	1.2181 7	1.1790 5	1.1865 3	1.1702 7	1.1563 1	1.1511 1	1.3576 2	1.2550 26	1.2236 35	1.2481 3	1.2462 21	1.2346 15	1.2370 2		1.1809 4	1.1736 4
	CCSD(T)=FULL					1.2615 16							1.3563 2	1.2768 11	1.2391 8	1.2999 2	1.2784 6	1.2312 4	1.3307 1		1.1803 4	1.1720 4

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	1.3281 87	1.2874 84	1.2877 81	1.2829 84	1.3040 84	1.3038 84
density functional	B1B95	1.2997 54	1.2590 54
density functional	B3LYP	1.3165 85	1.2730 82	1.3137 86	1.2689 83	1.3044 87	1.3047 85
Moller Plesset perturbation	MP2FC	1.3455 84	1.2877 80	1.3369 78	1.2857 80	1.3396 84	1.3395 84

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.