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IV.D.1. (XII.C.1.)

Geometry Comparison

CaH (Calcium monohydride)


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

Experimental bond length is 2.003  Å

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Calculated bond length in Å
Methods with predefined basis sets
semi-empirical PM3 2.096
PM6 1.995
composite G2 2.124
G3 2.048
G3B3 1.992
G4 1.988
CBS-Q 2.112

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) TZVP cc-pVDZ cc-pVTZ cc-pVQZ
hartree fock HF 2.063 2.167 2.176 2.168 2.124 2.122 2.122 2.051 2.054 2.100 2.172 2.053 2.050 2.047
ROHF   2.167 2.176 2.168 2.124 2.122 2.124 2.051 2.054   2.172 2.053 2.050 2.047
density functional LSDA 2.081 2.177 2.169 2.171 2.117 2.115 2.115 1.967 1.966 2.079 2.168 1.962 1.950  
SVWN   2.177     2.117 2.115 2.115 1.967 1.966 2.079   1.962 1.950  
BLYP 2.104 2.196 2.188 2.190 2.140 2.138 2.137 1.995 1.996 2.103 2.189 1.991 1.980  
B1B95 2.075 2.171 2.167 2.168 2.115 2.113 dnf 1.994 1.995 2.082 2.168 1.988 1.981  
B3LYP 2.085 2.177 2.173 2.173 2.123 2.121 2.121 1.996 1.997 2.089 2.171 1.990 1.981 1.979
B3LYPultrafine         2.123             1.989 1.981  
B3PW91 2.080 2.173 2.170 2.169 2.118 2.116 2.116 1.990 1.991 2.084 2.167 1.984 1.975  
mPW1PW91 2.076 2.169 2.167 2.166 2.115 2.113 2.112 1.991 1.992 2.081 2.163 1.985 1.977  
M06-2X 2.064 2.161 2.171 2.163 2.120 2.119 2.118 2.023 2.026 2.095 2.167 2.021 2.016  
PBEPBE 2.098 2.192 2.185 2.187 2.134 2.132 2.132 1.990 1.990 2.098 2.184 1.984 1.973  
PBEPBEultrafine         2.134             1.983 1.973  
PBE1PBE 2.078 2.171 2.171 2.169 2.118 2.118 2.116 1.995 1.995 2.085 2.167 1.988 1.980  
HSEh1PBE 2.078 2.173 2.170 2.169 2.118 2.116 2.116 1.995 1.996 2.085 2.167 1.988 1.980  
TPSSh   2.170 2.173 2.168 2.118 2.115 2.115 1.987       1.984 1.976  
Moller Plesset perturbation MP2 2.062 2.183 2.188 2.182 2.130 2.112 2.111 2.039 2.021 2.086 2.160 2.047 2.044 2.042
MP2=FULL 2.064 2.184 2.190 2.182 2.130 2.112 2.111 2.038 2.020 2.086 2.155 2.015 2.015 1.991
ROMP2 2.061 2.186 2.186 2.179 2.126 2.109 2.109 2.036 2.019 2.083 2.158 2.046 2.044  
MP3         2.137   2.108              
MP3=FULL         2.138   2.108              
MP4 2.081 2.204     2.142       2.024 2.092 2.165 2.049 2.050  
MP4=FULL   2.205     2.142       2.023     2.015 2.022  
B2PLYP         2.123                  
Configuration interaction CID   2.208 2.207 2.202 2.143     2.046 2.023 2.089        
CISD   2.220 2.214 2.212 2.150     2.047 2.025 2.092        
Quadratic configuration interaction QCISD 2.112 2.220 2.214 2.213 2.152 2.124 2.123 2.060 2.031 2.099 2.174 2.054 2.053  
QCISD(T)   2.221 2.216 2.214 2.154 2.125 2.125 2.061 2.030 2.101 2.175 2.054 2.053  
Coupled Cluster CCD 2.091 2.208 2.207 2.203 2.144 2.118 2.117 2.053 2.026 2.093 2.167 2.050 2.051  
CCSD         2.152           2.174 2.054 2.053 2.053
CCSD=FULL         2.152           2.168 2.021 2.028 2.006
CCSD(T)     2.215 2.214 2.154 2.125 2.125 2.060 2.030 2.101 2.175 2.054 2.053 2.053
CCSD(T)=FULL         2.154           2.170 2.021 2.027 2.003

Calculated bond length in Å
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF 2.130   2.161   2.152 2.071
density functional B3LYP 2.141   2.164   2.155 2.008
Moller Plesset perturbation MP2 2.144   2.171   2.167 2.077
Values that are outliers may reflect incorrect atom numbering for different levels of theory.
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