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Geometry Comparison

KH (Potassium hydride)


distance is atom 1 (K) to atom 2 (H)

Experimental bond length is 2.243  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 2.113
PM6 1.645
composite G2 2.322
G3 2.312
G3B3 2.250
G3MP2 2.312
G4 2.254
CBS-Q 2.323

Calculated bond length in 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
hartree fock HF 2.081 2.361 2.353 2.361 2.322 2.320 2.320 2.307 2.307 2.313 2.308 2.386    
ROHF   2.361 2.353 2.361 2.322 2.320 2.322 2.307 2.307   2.308 2.386    
density functional LSDA 2.094 2.300 2.287 2.294 2.254 2.254 2.254 2.200 2.216 2.238 2.195 2.303    
BLYP 2.130 2.342 2.324 2.336 2.295 2.297 2.297 2.252 2.252 2.275 2.247 2.348    
B1B95 2.103   2.318 2.324 2.283 2.283 2.281 2.246 2.246 2.266 2.244 2.342    
B3LYP 2.110 2.327 2.313 2.322 2.285 2.283 2.283 2.244 2.244 2.264 2.240 2.337    
B3LYPultrafine   2.327     2.285 2.282 2.282 2.243   2.263 2.240 2.336    
B3PW91 2.108 2.333 2.320 2.326 2.285 2.282 2.282 2.241 2.241 2.264 2.238 2.342    
mPW1PW91 2.103 2.327 2.316 2.321 2.280 2.278 2.278 2.239 2.238 2.261 2.236 2.338    
M06-2X 2.086 2.308 2.307 2.311 2.276 2.274 2.274 2.247 2.248 2.266 2.244 2.327    
PBEPBE 2.123 2.339 2.322 2.332 2.292 2.289 2.289 2.243 2.242 2.270 2.238 2.344    
PBEPBEultrafine   2.338     2.292 2.289 2.289 2.242   2.269 2.238 2.344    
PBE1PBE 2.102   2.315 2.321 2.281 2.281 2.279 2.240 2.240 2.262 2.237 2.337    
HSEh1PBE 2.102 2.325 2.313 2.320 2.281 2.278 2.278 2.240 2.239 2.260 2.236 2.336    
TPSSh 2.110 2.330 2.319 2.322 2.283 2.282 2.280 2.237 2.236 2.263 2.234 2.338    
wB97X-D 2.099 2.334 2.327 2.328 2.289 2.284 2.286 2.256 2.255 2.269 2.253 2.343 2.286  
B97D3 2.133 2.339 2.345 2.352 2.304 2.309 2.309 2.263 2.259 2.286 2.257 2.369   dnf
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
Moller Plesset perturbation MP2 2.104 2.382 2.367 2.378 2.316 2.296 2.296 2.262 2.243 2.282 2.238 2.377    
MP2=FULL 2.163 2.382 2.364 2.378 2.318 2.296 2.296 2.262 2.241 2.282 2.236 2.363    
ROMP2 2.104   2.367 2.378 2.318 2.296 2.296 2.263 2.243 2.282 2.238 2.377    
MP3         2.326   2.297       2.247 2.376    
MP3=FULL   2.394 2.372 2.388 2.321 2.300 2.297 2.271 2.245 2.288 2.245 2.362    
MP4   2.403     2.332       2.247   2.247 2.379    
MP4=FULL   2.402     2.332       2.245   2.245      
B2PLYP 2.105 2.343 2.329 2.338 2.293 2.285 2.284 2.250 2.244 2.268 2.240 2.349    
B2PLYP=FULL 2.105 2.345 2.328 2.338 2.295 2.285 2.288 2.250 2.243 2.268 2.239 2.344    
B2PLYP=FULLultrafine 2.106 2.342 2.327 2.338 2.293 2.285 2.285 2.250 2.243 2.268 2.238 2.343    
Configuration interaction CID   2.405 2.387 2.396 2.334     2.276     2.252      
CISD   2.419 2.396 2.409 2.342     2.277     2.253      
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
Quadratic configuration interaction QCISD   2.419 2.396 2.410 2.347 2.316 2.316 2.292 2.260 2.306 2.259 2.388    
QCISD(T)         2.347     2.291     2.255 2.388    
QCISD(T)=FULL         2.347   2.316       2.253      
QCISD(TQ)         2.348   2.317       2.255      
QCISD(TQ)=FULL         2.348   2.317       2.254      
Coupled Cluster CCD   2.405 2.387 2.396 2.336 2.306 2.307 2.282 2.252 2.298 2.254 2.380    
CCSD         2.348         2.306 2.259 2.388    
CCSD=FULL         2.348         2.306 2.257 2.374    
CCSD(T)         2.347 2.316 2.316 2.291 2.257 2.306 2.255 2.388    
CCSD(T)=FULL         2.347           2.253 2.374    
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

Calculated bond length in Å
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 2.346   2.459   2.353 2.346     2.319
ROHF                 2.322
density functional LSDA                 2.225
BLYP                 2.272
B1B95 2.355               2.267
B3LYP 2.356   2.445   2.320 2.309     2.262
B3LYPultrafine                 2.264
B3PW91                 2.264
mPW1PW91                 2.262
M06-2X                 2.267
PBEPBE                 2.265
PBEPBEultrafine                 2.265
PBE1PBE                 2.262
HSEh1PBE                 2.261
TPSSh                 2.261
wB97X-D 2.358   2.456   2.324 2.317     2.275
B97D3                 2.288
Moller Plesset perturbation MP2 2.365   2.459   2.374 2.363     2.317
MP2=FULL                 2.255
ROMP2                 2.317
MP3                 2.319
MP3=FULL                 2.261
MP4                 2.322
MP4=FULL                 2.262
B2PLYP                 2.281
B2PLYP=FULL                 2.260
B2PLYP=FULLultrafine                 2.260
Configuration interaction CID                 2.322
CISD                 2.326
Quadratic configuration interaction QCISD                 2.326
QCISD(T)                 2.326
QCISD(T)=FULL                 2.269
QCISD(TQ)                 dnf
QCISD(TQ)=FULL                 2.269
Coupled Cluster CCD                 2.322
CCSD                 2.326
CCSD=FULL                 2.272
CCSD(T)                 2.326
CCSD(T)=FULL                 2.269
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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