Density Functional Theory with Modified Dispersion Correction for Metals Applied to Self-Assembled Monolayers of Thiols on Au(111)

Table 3

(a) Physisorption energies of ethanethiol and butanethiol on Au(111). All energies are in eV. The physisorbed R-SH species are referenced against corresponding gas phase thiol. 𝐶₆ coefficients are in Ry*Bohr⁶. (b) Dissociative adsorption energy of dimethyl disulfide as a dithiol-adatom surface complex on Au(111) including the formation of adatom species from bulk Au atoms (Figure 2). The PBE and revPBE results are obtained from the PBE-D and revPBE-D results by subtracting the contribution from dispersion forces. 𝐶₆ coefficients are in Ry*Bohr⁶.

(a)

Adsorbate	CH3CH2SH	CH3(CH2)3SH
Experiment^a	−0.59	−0.70
PBE-D 𝐶6(Au) = 1040	−0.82	−1.00
revPBE-D 𝐶6(Au) = 1040	−0.81	−1.04
PBE	−0.31	−0.31
revPBE	0.20	0.31
PBE-D 𝐶6(Au) = 520	−0.68	−0.80
revPBE-D 𝐶6(Au) = 520	−0.56	−0.69

aExperimental data are taken from [40].

(b)

Method	Dissociative adsorption energy (eV)
Experiment^a	−1.30
PBE-D 𝐶6(Au) = 1040	−1.67
revPBE-D 𝐶6(Au) = 1040	−1.65
PBE	−0.91
revPBE	−0.24
PBE-D 𝐶6(Au) = 520	−1.47
revPBE-D 𝐶6(Au) = 520	−1.33

aExperimental data are taken from [40].