III.G.1.a.

Comparison of levels of theory for N-N

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	1.1997 8
	PM3	1.4649 41
	PM6	1.3204 45
composite	G2	1.2680 37
	G3	1.2762 43
	G3B3	1.3706 42
	CBS-Q	1.2377 26

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-pCVDZ	cc-pCVTZ	Sadlej_pVTZ
hartree fock	HF	1.3945 43	1.3116 43	1.3115 43	1.2933 43	1.3241 44	1.2759 43	1.3265 43	1.2736 43	1.3242 43	1.3235 43	1.3509 35	1.2907 45	1.2759 43	1.2610 41	1.1963 12	1.2770 43	1.2653 41	1.2161 9	1.1503 5	1.1423 5	1.0846 2
hartree fock	ROHF	1.1479 1	1.1187 3	1.1187 3	1.1329 2	1.1196 5	1.1124 3	1.1120 3	1.1063 3	1.0723 1	1.0720 1	1.1576 1		1.1119 3	1.1032 3	1.0676 1	1.0793 1	1.0688 1	1.0676 1
density functional	LSDA	1.4523 43	1.3907 43	1.3906 43	1.3766 43	1.3582 43	1.3581 43	1.3569 43	1.3538 43	1.3539 43	1.3543 43			1.3578 43	1.3506 43	1.1522 1	1.3569 43	1.1219 2	1.1521 1
	SVWN		1.3579 38			1.3469 36		1.3351 38
	BLYP	1.4986 43	1.4262 43	1.3348 26	1.3622 43	1.3387 40	1.3399 43	1.3386 43	1.2958 26	1.3856 43	1.3853 43			1.3429 42	1.3324 43		1.4229 31
	B1B95	1.4737 42	1.3965 42	1.3964 42	1.3800 42	1.3593 42	1.3612 42	1.3606 42	1.3585 42	1.3585 42	1.3580 42	1.1290 1		1.3612 42	1.3532 42	1.1547 2	1.3585 42	1.2120 9	1.1379 2
	B3LYP	1.4574 42	1.3540 39	1.3523 43	1.3355 43	1.3654 43	1.3651 43	1.3142 43	1.3120 43	1.2583 14	1.3098 37	1.3992 30	1.3213 45	1.3650 43	1.3018 40	1.2462 9	1.2512 19	1.2111 16	1.2422 9	1.1722 5	1.1618 5	1.1218 2
	B3LYPultrafine					1.3770 40		1.4290 10
	B3PW91	1.3375 14	1.3476 43	1.3474 43	1.3294 43	1.3050 41	1.3087 43	1.2713 26	1.3057 43	1.2535 14	1.3559 43			1.3084 43	1.3027 43		1.3939 31
	mPW1PW91	1.3302 14	1.3421 43	1.2811 15	1.3728 43	1.3021 40	1.3570 43	1.3031 43	1.3010 43	1.3513 43	1.3511 43			1.3035 43	1.2381 20		1.3850 31	1.0836 1
	M06-2X					1.3218 43
	PBEPBE	1.3645 14	1.4161 43	1.3065 14	1.2975 14	1.3785 43	1.3783 43	1.3771 43	1.3749 43	1.3748 43	1.3736 41	1.3925 33		1.3847 41	1.3719 43	1.1784 2	1.1102 1	1.2038 10	1.1658 2			1.1319 2
	PBEPBEultrafine					1.4158 34
	HSEh1PBE					1.3326 38
Moller Plesset perturbation	MP2FC	1.3692 14	1.3886 43	1.3885 43	1.3704 43	1.3773 43	1.3276 43	1.3283 43	1.3206 43	1.3197 40	1.3206 38		1.3286 45	1.3774 43	1.2899 27	1.1360 4	1.2702 18	1.1904 9	1.1307 4	1.1874 6	1.1734 6	1.1557 2
	MP2FU	1.3690 14	1.3209 20	1.3313 15	1.3193 15	1.3746 41	1.2885 25	1.2902 26	1.3191 43	1.2667 14	1.2638 14			1.2721 20	1.2476 15	1.1334 4	1.2363 13	1.1352 4	1.1383 2	1.1867 6	1.1713 6
	ROMP2	1.2464 1	1.1564 1	1.1564 1	1.1630 1	1.1530 1	1.1530 1	1.1525 1	1.1473 1	1.1473 1				1.1561 1	1.1460 1		1.1597 1	1.1470 1
	MP3					1.3064 39
	MP4	1.2843 2	1.2495 12			1.2817 19			1.2795 2	1.2946 13	1.3592 5				1.2798 10
	B2PLYP					1.3461 38		1.3401 39
Configuration interaction	CID	1.2891 3	1.2678 14	1.2381 12	1.2288 12	1.2578 25			1.2114 14	1.1972 3	1.2677 5
Configuration interaction	CISD	1.2901 3	1.2733 14	1.2436 12	1.2343 12	1.2581 23			1.2066 12	1.1990 3	1.2694 5
Quadratic configuration interaction	QCISD	1.3627 6	1.3406 28	1.2661 12	1.2935 14	1.2720 24	1.2766 16	1.2593 18	1.2472 19	1.2611 20	1.2237 10			1.2664 16	1.2017 12		1.1098 1	1.0928 1
Quadratic configuration interaction	QCISD(T)					1.2643 15	1.2649 1	1.2638 1	1.2695 3	1.3706 4	1.2575 1			1.1891 4	1.1755 4		1.1840 2	1.1666 2
Coupled Cluster	CCD	1.3461 6	1.2830 14	1.2509 12	1.2768 14	1.3199 26	1.2517 14	1.2514 14	1.2467 16	1.2132 10	1.2106 10			1.2560 16	1.2181 9		1.1335 3	1.1181 3		1.1928 4	1.1790 4
	CCSD					1.2542 15	1.2557 1	1.2545 1	1.2618 3	1.1908 3	1.2477 1			1.2553 1	1.2433 1
	CCSD(T)		1.1400 2			1.2673 16	1.2447 4	1.1668 4	1.2366 4	1.2853 6	1.2571 1	1.1035 1		1.2059 11	1.2222 14	1.1456 2	1.1652 7	1.1485 7	1.1369 2	1.1819 6	1.1681 6
	CCSD(T)=FULL					1.1767 8			1.1087 1					1.1764 6	1.1639 5	1.1432 2	1.1177 2	1.1410 3	1.1751 1	1.1811 6	1.1662 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	1.3120 43	1.2916 43	1.3086 43	1.2845 43	1.3019 43	1.3020 43
density functional	B1B95	1.4207 35	1.3987 35	1.2105 1	1.1833 1	1.2061 1	1.2063 1
density functional	B3LYP	1.3565 43	1.3323 43	1.3527 43	1.3255 43	1.3438 43	1.3434 42
Moller Plesset perturbation	MP2FC	1.4018 43	1.3454 43	1.3946 43	1.3396 43	1.3892 43	1.3894 43

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.