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Calculated Proton Affinity

20 10 26 10 44
Name Species   Species Name
imidizolyl anion C3H3N2- C3H4N2 4H-Imidazole

Bonding changes

Bond type H-C changed by +2
Bond type H-N lost 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 G1 1389
G2MP2 1393
G2 1357
G3 1358
G3B3 1361
G4 1360
CBS-Q 1352

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 1759 1460 1460 1432 1469 1472 1427 1455 1457 1482   1438 1462 1451 1432 1435 1435
density functional LSDA 1664 1407 1407 1380 1397 1398 1341 1368 1369 1399   1348 1383 1359 1339 1341  
BLYP 1702 1459 1459 1431 1448 1450 1383 1418 1419 1450   1394 1431 1407      
B1B95 1689 1439 1439 1414 1434 1449 1387 1414 1415 1440   1397 1423 1407 1386 1390  
B3LYP 1702 1452 1452 1425 1446 1448 1389 1420 1421 1450   1398 1431 1410 1387 1390  
B3LYPultrafine         1446             1398 1431 1410 1387 1390  
B3PW91 1697 1443 1443 1419 1439 1441 1392 1417 1418 1444   1400 1428 1411      
mPW1PW91 1697 1441 1441 1417 1438 1440 1391 1417 1418 1444   1401 1427 1411 1391 1394  
M06-2X 1699 1432 1432 1404 1421 1423 1375 1401 1402 1427   1383 1411 1392 1376 1377  
PBEPBE 1693 1442 1442 1417 1433 1436 1377 1408 1409 1437   1388 1420 1399 1375 1378  
PBEPBEultrafine         1433             1388 1420 1399 1375 1378  
PBE1PBE 1697 1437 1437 1413 1434 1434 1386 1413 1414 1440   1395 1423 1406 1386 1389  
HSEh1PBE 1697 1438 1438 1413 1434 1437 1233 1413 1414 1440   1395 1423 1406 1386 1388  
TPSSh   1450 1450 1426 1446 1448 1397 1424   1451   1407 1435 1418 1397 1400  
wB97X-D     1447   1444   1396   1423     1405 1396 1416   1400  
B97D3   1463     1456   1401   1433   1402 1412   1424   1403  
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 1784 1458 1458 1420 1418 1434 1373 1395 1408 1419   1386 1415 1385 1358    
MP2=FULL 1784 1458 1458 1420 1418 1434 1373 1395 1408 1422   1386 1415 1387 1359 1363  
MP3         1448   1375         1423 1448        
MP3=FULL         1448   1410         1423 1448 1425      
MP4   1480     1443       1434     1411   1410 1385 1384  
MP4=FULL   1480                     1442 1412      
B2PLYP 1732 1455 1455 1424 1439 1445 1386 1415 1419 1442   1397 1428 1405 1380 1382  
B2PLYP=FULL 1732 1455 1455 1424 1439 1445 1386 1414 1419 1443   1397 1428 1405 1380    
Configuration interaction CID   1474 1474 1439 1452     1435                  
CISD   1475 1475 1440 1453     1436                  
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   1491 1491 1452 1457 1472 1415 1437 1450 1462     1456 1430 1406    
QCISD(T)         1452             1421 1451 1422      
Coupled Cluster CCD   1487 1487 1448 1452 1467 1412 1432 1445 1457   1425 1451 1426 1402    
CCSD         1456             1428 1455 1429 1405    
CCSD=FULL         1455             1428 1455 1431 1406    
CCSD(T)         1452             1421 1451 1421 1397    
CCSD(T)=FULL         -7023             1421 1452        
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 1412 1450 1408 1444 1408 1408     1443
density functional B3LYP 1399 1423 1392 1414 1396 1396     1401
PBEPBE                 1390
Moller Plesset perturbation MP2 1391 1396 1382 1384 1386 1386      
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.