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Calculated Proton Affinity

20 10 26 10 44
Name Species   Species Name
cylopentadienyl anion C5H5- C5H6 1,3-Cyclopentadiene

Bonding changes

Bond type H-C changed by +1
Proton Affinities (kJ/mol)
Proton Affinities in kJ/mol
Methods with predefined basis sets
composite G1 1476
G2MP2 1476
G4 1439

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 cc-pV(T+d)Z daug-cc-pVTZ
hartree fock HF 1865 1557 1557 1546 1564 1567 1511 1540 1541 1571   1522 1542 1532 1509 1507 1532 1513
density functional BLYP 1791 1546 1546 1533 1537 1539 1467 1500 1500 1535     1505 1488     1488  
B1B95 1788 1538 1538 1530 1528 1534 1479 1530 1505 1532     1505 1490 1469 1473 1490  
B3LYP 1798 1545 1545 1533 1539 1540 1476 1505 1505 1538   1484 1509 1493 1469 1473 1493  
B3LYPultrafine         1539                     1473    
B3PW91 1795 1537 1537 1528 1533 1534 1480 1503 1503 1533     1507 1494     1494  
mPW1PW91 1798 1532 1537 1527 1528 1530 1475 1499 1503 1533     1503 1494     1494  
M06-2X     1525   1515                          
PBEPBE 1786 1532 1532 1521 1524 1525 1463 1491 1491 1523     1495 1480     1480  
PBE1PBE         1528                          
HSEh1PBE   1533     1528   1474             1489        
TPSSh         1538   1484     1539       1499        
wB97X-D     1544   1540   1486   1509     1493 1486 1501   1485    
B97D3   1554     1547   1486   1515   1483 1496   1504   1484    
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 cc-pV(T+d)Z daug-cc-pVTZ
Moller Plesset perturbation MP2 1880 1549 1549 1531 1521 1535   1484 1494 1516   1276 1496 1471   1445    
MP2=FULL   1549 5018 1531 1521 1536 1466 1483 1494       1496 1474        
MP3         1550                          
MP3=FULL         1550   1501                      
B2PLYP         1535                 1488        
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 cc-pV(T+d)Z daug-cc-pVTZ
Quadratic configuration interaction QCISD   1582 1582 1564 1556 1569 1504 1522 1532       1533          
Coupled Cluster CCD   1581 1581 1563 1555 1569 1504 1520         1532          
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 cc-pV(T+d)Z 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 1516 1535 1510 1528 1512 1512     1523
density functional B3LYP 1505 1512 1491 1498 1503 1503     1484
PBEPBE                 1471
Moller Plesset perturbation MP2 1497 1493 1482 1471 1492 1492     1461
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.