Mod:Hunt Research Group: Using SMD on ILs

This page explains how to use the SMD model to simulate an ionic liquid environment in Gaussian calculations. First read the previous general section on SMD. The SMD model is explained in detail in the original paper here. Its use on ILs is similarly explained here. Many useful solvent parameters are also available in this paper.

Types of SMD model for ILs

3 types of SMD for ILs have been defined.

• SMD The standard SMD model. All parameters are determined for the particular IL (or a very similar one) being used as the solvent environment.
• SMD-GIL The generic ionic liquid model. The average values above are used for all parameters, except φ and ψ, which are simply calculated from the chemical formula of the IL.
• SMD-PGPThe partial generic parameters model. Any parameter which has been measured for that IL is used. For any parameters which you do not have values for, use the average values.

Example: [C₄C₁Im][NTf₂]

• All parameters for this IL have been measured, and can be found in reference 2. That means we can use the standard SMD method.
• To get a value for φ take the number of aromatic carbon atoms (3) and divide by the number of non-hydrogen atoms (25). φ = 0.12.
• To get a value for ψ take the number of electronegative halogen atoms (6) and divide by the number of non-hydrogen atoms (25). ψ = 0.24.
• To define these parameters place the following line at the bottom of the input file (include one blank line before and at least one blank line after):
• eps=11.52 epsinf=2.037 SurfaceTensionAtInterface=53.97 HBondAcidity=0.259 HBondBasicity=0.238 CarbonAromaticity=0.12 ElectronegativeHalogenicity=0.24
• see following data for other ILs

calculations using SMD in Orca

This is not fully tested

Easiest is to use the SMD keyword for one of the prescribed solvents

! DLPNO-CCSD(T) SMD(ethanol) defGrid3 def2-TZVP def2-TZVP/C verytightscf TightPNO 

Then you can define a solvent, to call smd you have to give it a solvent, then you can "overwrite" with the IL solvent parameters, here they are for SMD-GIL

note that the refractive index for the IL is given only for 25 ºC so I have set that for 20ºC to the same value, this needs checking

also on comparing the radii used there is something fishy with O radii!

may need to use "radius[8] x.xx" to correct

! DLPNO-CCSD(T) def2-TZVP def2-TZVP/C verytightscf TightPNO
%cpcm
   smd true
   smdsolvent "ethanol"
   rsolv 0.0
   epsilon 11.5
   soln 1.43
   soln25 1.43
   sola 0.229
   solb 0.265
   solg 61.24
   solc 0.25
   solh 0.0
 end
%pal nprocs 16 end
%maxcore 2400

alpha and beta database

Solvent	alpha	beta	eps	n2	surface tension	reference
[C4C1Im][BF4]	0.229	0.265	11.50	1.43	61.24	Bernales 2012 http://pubs.acs.org/doi/abs/10.1021/jp304365v} SMD input database Here we will keep a database of SMD parameters used by the group. Please add any IL you use, so no-one else has to re-do the research for the parameters! Please follow the template provided so that it is clear where you get each value from. SMD-GIL all values from Name in Gaussian input file Value Reference Comments/calculations eps 11.50 epsinf (n2) 2.0449 Value given in reference is n=1.43, it has been squared to give epsinf=2.0449 SurfaceTensionAtInterface 61.24 HBondAcidity (α) 0.229 HBondBasicity (β) 0.265 CarbonAromaticity (φ) compute for your system ElectronegativeHalogenicity (ψ) compute for your system eps=11.50 epsinf=2.0449 SurfaceTensionAtInterface=61.24 HBondAcidity=0.229 HBondBasicity=0.265 CarbonAromaticity=x.xx ElectronegativeHalogenicity=x.xx [C4C1Im][BF4] all values from Name in Gaussian input file Value Reference Comments/calculations eps 11.70 epsinf n2) 2.0207 Value given in reference is n=1.4215, it has been squared to give epsinf=2.0207 SurfaceTensionAtInterface 67.07 HBondAcidity (α) 0.263 Kamlet-Taft 0.627 HBondBasicity (β) 0.320 Kamlet-Taft 0.376 CarbonAromaticity (φ) 0.2000 There are 15 non-H atoms, 3 are aromatic C atoms, value=3/15=0.2000 ElectronegativeHalogenicity (ψ) 0.2667 There are 15 non-H atoms, 4 are electronegative halogen atoms, value =4/15=0.2667 eps=11.70 epsinf=2.0207 SurfaceTensionAtInterface=67.07 HBondAcidity=0.263 HBondBasicity=0.320 CarbonAromaticity=0.2000 ElectronegativeHalogenicity=0.2667 [C4C1Im][PF6] all values from Name in Gaussian input file Value Reference Comments/calculations eps 11.40 epsinf n2) 1.9853 Value given in reference is n=1.4090, it has been squared to give epsinf=1.9853 SurfaceTensionAtInterface 70.24 HBondAcidity (α) 0.266 Kamlet-Taft 0.634 HBondBasicity (β) 0.216 Kamlet-Taft 0.207 CarbonAromaticity (φ) 0.1765 There are 17 non-H atoms, 3 are aromatic C atoms, value=3/17=0.1765 ElectronegativeHalogenicity (ψ) 0.3529 There are 17 non-H atoms, 4 are electronegative halogen atoms, value =6/17=0.3529 eps=11.40 epsinf=1.9853 SurfaceTensionAtInterface=70.24 HBondAcidity=0.266 HBondBasicity=0.216 CarbonAromaticity=0.1765 ElectronegativeHalogenicity=0.3529 [C4C1Im][NTf2] all values from Name in Gaussian input file Value Reference Comments/calculations eps 11.52 epsinf n2) 2.0366 Value given in reference is n=1.4271, it has been squared to give epsinf=2.0366 SurfaceTensionAtInterface 53.97 HBondAcidity (α) 0.259 Kamlet-Taft 0.617 HBondBasicity (β) 0.238 Kamlet-Taft 0.243 CarbonAromaticity 0.1200 There are 25 non-H atoms, 3 are aromatic C atoms, value =3/25=0.1200 ElectronegativeHalogenicity 0.2400 There are 25 non-H atoms, 6 are electronegative halogen atoms, value =6/25=0.2400 eps=11.52 epsinf=2.0366 SurfaceTensionAtInterface=53.97 HBondAcidity=0.259 HBondBasicity=0.238 CarbonAromaticity=0.1200 ElectronegativeHalogenicity=0.2400 [C4C1Im][OTf] Name in Gaussian input file Value Reference Comments/calculations eps 12.90 Page 1495, number 11 on the list. epsinf n2) 2.0665 n=1.43755, has been squared to give epsinf=2.0665. Can be found in Table 1, 3rd row. SurfaceTensionAtInterface unknown HBondAcidity (α) 0.263 Kamlet-Taft 0.625 HBondBasicity (β) 0.374 Kamlet-Taft 0.464 CarbonAromaticity 0.1667 - There are 18 non-H atoms, 3 are aromatic C atoms, value=3/18=0.1667. ElectronegativeHalogenicity 0.1667 - There are 18 non-H atoms, 3 are electronegative halogen atoms, value=3/18=0.1667. eps=12.90 epsinf=2.0665 SurfaceTensionAtInterface=XX HBondAcidity=0.263 HBondBasicity=0.374 CarbonAromaticity=0.1667 ElectronegativeHalogenicity=0.1667 [C4C1Im][SCN] Name in Gaussian input file Value Reference Comments/calculations eps 13.70 epsinf (n2) 2.3691 n=1.53921, has been squared to give epsinf=2.3691 (error in some database calcs with n=1.5436 n2=2.3827) SurfaceTensionAtInterface 68.34 η=45.41 (mN.m-1) converts to 45.41*1.439= cal mol-1 Å-2=65.34 HBondAcidity (α) 0.18 Kamlet-Taft 0.43 HBondBasicity (β) 0.52 Kamlet-Taft 0.71 CarbonAromaticity 0.2308 There are 13 non-H atoms, 3 are aromatic C atoms, value=3/13=0.2308 ElectronegativeHalogenicity 0.0 There are no electronegative halogen atoms, value=0.0 eps=13.70 epsinf=2.3691 SurfaceTensionAtInterface=68.34 HBondAcidity=0.18 HBondBasicity=0.52 CarbonAromaticity=0.2308 ElectronegativeHalogenicity=0.0 Molten salt [Li+,Na+,K+][CO32-] Name in Gaussian input file Value Reference Comments/calculations MolarVolume 57 molar volume Li2CO3 68 Na2CO3 92 K2CO3 124 Å3/molecule, average is 95 and 95*0.6022=57 at T=1.1Tm Tabs 900 Absolute Temperature in K ie 298+600≈900 ??? ThermalExansionCoefficient estimate 20*10-6 K-1 at T=1.1Tm (this is not working!) eps 3 estimated value epsinf n2) 2.25 refractive index Na2CO3 1.489-1.535, Li2CO3 1.428-1.572 K2CO3 1.426-1.541 taking a "mid" value 1.52=2.25 SurfaceTensionAtInterface 273 used surface tension of Na/K/CO3 mixture 50 mol % K2CO3 at 810 ºC , 190.0 dynes/cm HBondAcidity (α) 0.00 - There are no H-atoms so H-bond acidity is zero H-bond basicity computations result in proton transfer, NO3 ≈0.74-0.81, Cl ≈0.95-0.98, we assume it is even stronger due to -2 charge HBondBasicity (β) 0.99 CarbonAromaticity 0.00 - There are no aromatic C atoms ElectronegativeHalogenicity 0.00 - There are no halogen atoms Stoichiometry=C2O62Li2Na2K2 MolarVolume=57.0 Tabs=900 eps=3.0 epsinf=2.25 SurfaceTensionAtInterface=273 HBondAcidity=0.0 HBondBasicity=0.99 CarbonAromaticity=0.0 ElectronegativeHalogenicity=0.0 Bismuth halometallate ionic liquid, parameterised for [C2C1Im][BiCl4] Name in Gaussian input file Value Reference Comments/calculations eps 11.5 From SMD-GIL epsinf 2.04 From SMD-GIL SurfaceTensionAtInterface 61.24 From SMD-GIL HBondAcidity (α) 0.275 Calculated using HBondBasicity (β) 0.070 Calculated using CarbonAromaticity 0.231 From stoichiometry ElectronegativeHalogenicity 0.308 From stoichiometry eps=11.5 epsinf=2.04 HBondAcidity=0.275 HBondBasicity=0.070 SurfaceTensionAtInterface=61.24 CarbonAromaticity=0.231 ElectronegativeHalogenicity=0.308 Example table Name in Gaussian input file Value Reference Comments/calculations eps epsinf SurfaceTensionAtInterface HBondAcidity (α) HBondBasicity (β) CarbonAromaticity ElectronegativeHalogenicity eps= epsinf= SurfaceTensionAtInterface= HBondAcidity= HBondBasicity= CarbonAromaticity= ElectronegativeHalogenicity= References