Table 1. Equilibrium Structure of the 1Ag Statea.
| basis setsb | RCC [Å] | RCH [Å] | θHCH [deg] | |
|---|---|---|---|---|
| all-ele. | 8s4p1d (AGP) | 1.3288(9) | 1.0788(7) | 117.04(11) |
| 8s4p1d (n = 8) | 1.3262(9) | 1.0801(6) | 117.03(11) | |
| 9s5p2d (n = 8) | 1.3257(9) | 1.0798(6) | 117.09(11) | |
| 8s4p1d (n = 12) | 1.3305(9) | 1.0798(6) | 117.16(11) | |
| 9s5p2d (n = 12) | 1.3313(9) | 1.0793(6) | 117.03(11) | |
| SR-ECP | [1s1p1d] | 1.3303(3) | 1.0783(2) | 116.89(5) |
| [2s1p1d] | 1.3282(8) | 1.0786(16) | 116.82(14) | |
| [1s2p1d] | 1.3295(6) | 1.0787(3) | 117.07(9) | |
| [2s2p]c | 1.3284(12) | 1.0791(9) | 116.94(9) | |
| [2s2p1d] | 1.3289(6) | 1.0790(5) | 117.01(9) | |
| [2s2p2d] | 1.3283(3) | 1.0789(2) | 117.08(5) | |
| SR-NCP | [1s2p1d] | 1.3347(11) | 1.0809(12) | 117.09(22) |
| HF-NCP | [1s2p1d] | 1.3353(11) | 1.0808(13) | 117.09(22) |
| CCSD(T)30 | 1.3307(3) | 1.0809(3) | 117.12(3) | |
| LDA34 | 1.3266 | 1.0958 | 116.66 | |
| MP234 | 1.3386 | 1.0848 | 116.64 | |
| MP231 | 1.331046 | 1.080564 | 117.3 | |
| B3LYP34 | 1.3289 | 1.0850 | 116.52 | |
| B3LYP60 | 1.324 | 1.085 | 116.32 | |
| exptl58 | 1.3370 | 1.0860 | 117.62 | |
| exptl61 | 1.330(5) | 1.079(5) | ||
| exptl62 | 1.334(2) | 1.081(2) | 117.36(17) | |
| exptl63 | 1.336 | 1.076 | 118.02 | |
| exptl59 | 1.339 | 1.085 | 117.8 | |
a
In this table, we report the structural optimization of the 1Ag ground state of the C2H4 molecule for different basis sets.
b
For the pseudopotential basis sets, we have indicated only the carbon atom contracted orbitals made of (5s5p5d) primitive Gaussians. The hydrogens’ basis set was fixed to (4s3p)/[1s1p] contracted Gaussian orbitals.
c
This basis set is built of (4s4p)/[2s2p] contracted orbitals for the carbon atom and (2s2p)/[1s1p] orbitals for the hydrogen atoms. The three-body Jastrow factor is built with (3s2p)/[2s2p] orbitals for the carbon atoms and (2s1p)/[1s1p] orbitals for the hydrogens.