Supplementary Materials
Probing the early stages of salt nucleation—
experimental and theoretical investigations of
sodium/potassium thiocyanate cluster anions
S. H. M. Deng, Xiang-Yu Kong,† and Xue-Bin Wang a)
Physical Sciences Division, Pacific Northwest National Laboratory, 902 Battelle
Boulevard, P. O. Box 999, MS K8-88, Richland, Washington 99352, United States
a)
Author to whom correspondence should be addressed. Electronic mail:
xuebin.wang@pnnl.gov
†
Visiting student supported by PNNL alternate sponsored fellowship. Permanent address:
Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular
Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing
100190, China.
S1
–
–
Figure S1. Low temperature 20 K photoelectron spectra of Na4 (SCN)5 and K 5 (SCN)6 at
157 nm (7.867 eV). Blue and red highlight spectral bands from the singly charged and
doubly charged dimer species, respectively. The extra spectral bands could be due to the
existence of unknown impurities.
S2
Computational details on the singly charged sodium thiocyanate cluster anions
To choose the method for the calculation, we started on the SCN– anion using several
functionals with 6-311+G(d) basis set for every atom and compared those results with the
reported one (J. Chem. Phys. 98, 800 (1993)).42 B3LYP, B3PW91, M06-2X, MP2,
ωB97XD, and PBEPBE were used for SCN– anion optimizations. All results including
VDEs and ADEs were listed in the Table S1. The best results were calculated using
ωB97XD functional, and the results with B3LYP were also acceptable. Moreover,
CCSD(T) single point calculation on geometry optimized using B3LYP was conducted as
well, but the obtained VDE was too low. ADE calculations were skipped for PBEPBE
and CCSD(T) since both calculated VDEs were smaller than the measured EA. Therefore,
ωB97XD/6-311+G(d) was chosen as our initial calculation method.
Table S1. Calculated VDEs and ADEs of SCN– anion using different functionals.
EA(NCS)=3.537 eV
B3LYP
B3PW91
M06-2X
MP2
ωB97XD
PBEPBE
CCSD(T) at B3LYP geometry
VDE
3.540
3.538
3.652
3.782
3.567
3.469
3.099
ADE
3.506
3.503
3.623
3.651
3.534
-------------
Calculation of Na(SCN)–2 cluster
The optimization led to a linear structure of (SCN-Na-NCS)–, even started with initial
linear (NCS-Na-SCN)– and nonlinear structures. The calculated B97XD/6-311+G(d) //
B3LYP/6-311+G(d) VDE of 5.02 eV (Table 1) agrees well with the experimental VDE of
5.19 eV, and also in excellent accord with the calculated VDE of 5.01 eV reported in a
previous calculation (Inorg. Chem. 48, 10231 (2009)).33
S3
23-A ΔE=1.20 kcal/mol
VDE=4.874 eV
23-B ΔE=5.94 kcal/mol
VDE=5.371 eV
23-C ΔE=7.20 kcal/mol
VDE=5.381 eV
Figure S2.
Low-lying isomers for Na2 (SCN)–3 .
This cluster was constructed by
elongating the Na(SCN)–2 cluster by adding a third NaSCN unit at the end of the linear
structure, or considering the metal-in-the-center and ligands-stay-outside pattern. Results
showed the elongated structure had a higher relative energy. B97XD/6-311+G(d) //
B3LYP/6-311+G(d) were used for calculations.
S4
34-A ΔE=2.43 kcal/mol
VDE=5.779 eV
34-C ΔE=4.11 kcal/mol
VDE=5.839 eV
34-B ΔE=3.12 kcal/mol
VDE=5.903 eV
34-D ΔE=4.27 kcal/mol
VDE=5.836 eV
34-E ΔE=16.92 kcal/mol
VDE=6.009 eV
Figure S3. Low-lying isomers for Na3 (SCN)–4 . We considered the Na…NSC interaction,
metal-in-the-center and high symmetry elements to construct many initial guess
structures for this species. Six stable structures were obtained with the calculated VDEs
ranging from 5.78 to 6.01 eV. B97XD/6-311+G(d) // B3LYP/6-311+G(d) were used for
calculations.
S5
45-A ΔE=0.031kcal/mol
VDE=5.867 eV
45-B ΔE=0.57 kcal/mol
VDE=5.680 eV
45-D ΔE=4.85 kcal/mol
VDE=5.901 eV
45-C ΔE=0.59 kcal/mol
VDE=6.033 eV
45-F ΔE=5.37 kcal/mol
VDE=5.808 eV
45-E ΔE=5.30 kcal/mol
VDE=5.774 eV
S6
45-H ΔE=8.63 kcal/mol
VDE=4.891 eV
45-G ΔE=6.34 kcal/mol
VDE=6.191 eV
45-I ΔE=9.56 kcal/mol
VDE=5.249 eV
45-J ΔE=14.62 kcal/mol
VDE=4.894 eV
45-K ΔE=14.63 kcal/mol
VDE=4.893 eV
Figure S4. Low lying isomers for Na4 (SCN)–5 . Many initial structures were considered
and 10 stable structures were obtained with relative energy less than 10 kcal/mol
(calculated VDEs were in the range of 4.89 to 6.19 eV). B97XD/6-311+G(d) //
B3LYP/6-311+G(d) were used for calculations.
S7
56-A ΔE=1.36 kcal/mol
VDE=6.122 eV
56-B ΔE=3.04 kcal/mol
VDE=6.111 eV
56-D ΔE=4.71 kcal/mol
VDE=6.197 eV
56-C ΔE=3.77 kcal/mol
VDE=6.192 eV
56-E ΔE=7.54 kcal/mol
VDE=6.074 eV
56-F ΔE=9.90 kcal/mol
VDE=6.164 eV
S8
56-H ΔE=14.64 kcal/mol
VDE=6.365 eV
56-G ΔE=12.56 kcal/mol
VDE=6.125 eV
56-J ΔE=20.69 kcal/mol
VDE=5.726 eV
56-I ΔE=19.56 kcal/mol
VDE=5.321 eV
56-K ΔE=23.23 kcal/mol
VDE=6.246 eV
56-L ΔE=24.59 kcal/mol
VDE=5.912 eV
Figure S5 Low-lying isomers for Na5 (SCN)–6 . Many initial structures were considered but
finally seven stable structures were obtained with relative energy less than 10 kcal/mol
(calculated VDEs were in the range of 6.07 to 6.20 eV). B3LYP/6-311+G(d) was used
for geometry optimization and ωB97XD/6-311+G(d) was used for the single point energy
calculation.
S9
67-A ΔE=5.90 kcal/mol
VDE=6.333 eV
67-B ΔE=9.18 kcal/mol
VDE=6.054 eV
67-C ΔE=10.20 kcal/mol
VDE=6.276 eV
67-D ΔE=10.43 kcal/mol
VDE=6.350 eV
67-E ΔE=10.62 kcal/mol
VDE=6.023 eV
67-F ΔE=11.17 kcal/mol
VDE=6.097 eV
S10
67-H ΔE=14.85 kcal/mol
VDE=6.393 eV
67-G ΔE=11.83 kcal/mol
VDE=5.943eV
67-J ΔE=25.91 kcal/mol
VDE=5.862 eV
67-I ΔE=21.00 kcal/mol
VDE=6.306 eV
67-K ΔE=27.52 kcal/mol
VDE=5.955 eV
67-L ΔE=29.87 kcal/mol
VDE=6.563 eV
S11
67-M ΔE=30.89 kcal/mol
VDE=6.405 eV
Figure S6. Low lying isomers for Na6 (SCN)–7 . This cluster was constructed by adding a
NaSCN unit to Na5 (SCN)–6 cluster. A structure based on crystal structure was constructed
as well. Many initial structures were considered but finally three stable structures were
obtained with relative energy less than 10 kcal/mol (calculated VDEs were in the range of
6.05 to 6.33 eV). B3LYP/6-311+G(d) was used for geometry optimization and
ωB97XD/6-311+G(d) was used for the single point energy calculation.
S12
-0.482
0.073
-0.591
-0.350
0.149
0.899
-0.748
-0.609
0.086
-0.319
0.787
0.866
-0.306
0.155
-0.649
-0.760
0.765
0.765
0.140
0.866
-0.307
-0.266
-0.294
-0.284
0.155
0.797
-0.773
-0.679
0.784
0.124
0.114
-0.654
-0.637
0.826
0.155
-0.278
0.789
-0.775
0.160
-0.662 0.804
0.130
-0.272
-0.282
0.725
-0.297
0.150
-0.351
0.122
-0.556
0.718
-0.734
-0.292
0.172
0.798
-0.274
-0.628
0.153 -0.764
0.766
0.168
-0.638
-0.252
-0.646
-0.773 0.157 -0.249
-0.633
0.162
-0.267
0.726
0.778
-0.255
0.744
0.797
0.169
-0.293
-0.737
-0.686 0.762
0.130
0.153
-0.299
Figure S7. NBO natural atomic charge distribution for [Nax(SCN)x+1]– (x = 0 to 6) and
[Na8(SCN)10]2–. For the x = 5 cluster, the missing numbers of the charges for C, N, S, and
Na are the same as those for each respective atom that is labelled.
S13
Figure S8. Mass spectrum of potassium thiocyanate clusters. Triply charged anions were
labeled in green.
S14
2–
Figure S9. Low temperature photoelectron spectra of K13 (SCN)15 at (a) 193, (b) 157 nm, and
combined both in (c). In (c), a bandwidth change can be observed clearly, which indicates the
existence of Repulsive Coulomb Barrier (RCB), a hallmark of multiply charged anions.
S15
Table S2. Calculated cluster size dimensions (in Å)
Clusters
SCN–
Na(SCN)–2
Na2 (SCN)–3
Na3 (SCN)–4
Na4 (SCN)–5
Na5 (SCN)–6
Na6 (SCN)–7
Na8 (SCN)2–
10
Na9 (SCN)2–
11
Na10 (SCN)2–
12
Na11 (SCN)2–
13
Na12 (SCN)2–
14
Length
2.844
10.069
8.258
9.694
9.783
8.835
9.432
13.570
11.902
13.447
15.037
22.564
S16
Width
Height
8.258
3.854
9.696
4.856
8.080
10.426
11.246
10.131
13.234
9.608
2.643
3.811
4.746
4.334
6.281
5.906
10.981
9.553
8.536
7.364