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Calculated Proton Affinity

20 10 26 10 44
Name Species   Species Name
imidizolyl anion C3H3N2- C3H4N2 1H-Imidazole

Bonding changes

Bond type H-C changed by +1
Bond type C-N changed by +1
Bond type C=N changed by -1
Bond type N-N lost 1
Bond type C=C gained 1
Proton Affinities (kJ/mol)
Proton Affinities in kJ/mol
Methods with predefined basis sets
composite G2 1417
G3 1420
G3B3 1422
G4 1421
CBS-Q 1418

Proton Affinities in kJ/mol
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 aug-cc-pVDZ aug-cc-pVTZ daug-cc-pVTZ
hartree fock HF 1791 1550 1550 1525 1510 1521 1481 1498 1508 1528   1491 1511 1503 1478 1487 1487
density functional LSDA   1516     1477 1485 1430 1454 1462 1490   1441 1474 1453 1429 1435  
BLYP 1740 1536 1536 1512 1501 1509 1446 1478 1486 1514   1462 1496 1475      
B1B95 1742 1533 1533 1513 1498 1498 1460 1482 1490 1512   1472 1496 1484 1459 1467  
B3LYP 1747 1539 1539 1515 1502 1511 1456 1482 1491 1516   1469 1499 1482 1455 1462  
B3LYPultrafine         1502             1469 1499 1482 1455 1462  
B3PW91 1746 1535 1535 1514 1501 1510 1464 1484 1492 1515   1475 1499 1486      
mPW1PW91 1747 1535 1535 1515 1501 1510 1464 1484 1493 1516   1476 1499 1487 1462 1470  
M06-2X 1750 1525 1525 1504 1486 1495 1450 1469 1477 1501   1459 1485 1468 1450 1453  
PBEPBE 1739 1528 1528 1506 1494 1503 1447 1474 1483 1508   1462 1491 1474 1446 1453  
PBEPBEultrafine         1494             1462 1491 1474 1446 1453  
PBE1PBE 1748 1532 1532 1511 1497 1497 1459 1481 1490 1512   1471 1496 1483 1458 1465  
HSEh1PBE 1748 1533 1533 1511 1497 1507 1306 1480 1490 1512   1471 1496 1483 1458 1465  
TPSSh   1533 1533 1514 1502 1511 1463 1485   1516   1475 1500 1487 1462 1469  
wB97X-D     1543   1505   1466   1496     1478 1470 1490   1473  
B97D3   1544     1512   1466   1501   1471 1481   1493   1473  
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 aug-cc-pVDZ aug-cc-pVTZ daug-cc-pVTZ
Moller Plesset perturbation MP2 1795 1532 1532 1498 1482 1503 1446 1463 1481 1495   1460 1486 1465 1432 1440  
MP2=FULL 1795 1532 1532 1498 1483 1504 1447 1463 1482 1498   1460 1486 1470 1433 1446  
MP3         1500   1471         1484 1505 1489      
MP3=FULL         1501   1472         1485 1506 1494      
MP4   1544     1491       1491     1469 1496 1474 1442    
MP4=FULL   1544     1492       1492       1497 1479 1443    
B2PLYP 1765 1537 1537 1509 1495 1508 1452 1476 1487 1509   1465 1494 1476 1447 1454  
B2PLYP=FULL 1765 1537 1537 1509 1495 1508 1452 1476 1488 1510   1466 1494 1477 1447 1456  
Configuration interaction CID   1553 1553 1522 1504     1490                  
CISD   1553 1553 1522 1504     1490                  
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 aug-cc-pVDZ aug-cc-pVTZ daug-cc-pVTZ
Quadratic configuration interaction QCISD   1555 1555 1521 1501 1521 1468 1484 1501 1515   1482 1505 1488 1456    
QCISD(T)         1496             1476   1481 1448    
Coupled Cluster CCD   1553 1553 1520 1501 1521 1470 1484 1502 1515   1483 1506 1488 1458    
CCSD         1501             1482 1506 1488 1457    
CCSD=FULL         1502               1507 1493 1458    
CCSD(T)         1497             1476 1501   1449    
CCSD(T)=FULL         1497             1477 1502 1486 1450    
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 aug-cc-pVDZ aug-cc-pVTZ daug-cc-pVTZ

Proton Affinities in kJ/mol
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD cc-pVTZ-PP aug-cc-pVTZ-PP Def2TZVPP
hartree fock HF 1494 1481 1493 1480 1499 1499     1495
density functional B3LYP 1482 1471 1477 1466 1488 1488     1473
PBEPBE                 1465
Moller Plesset perturbation MP2 1463 1449 1458 1444 1468 1468     1455
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.