1
Supplemental Material
for
The ionic states of iodobenzene studied by photoionization and ab
initio configuration interaction and DFT computations
Michael H. Palmer,1a Trevor Ridley,1 Søren Vrønning Hoffmann,2 Nykola C. Jones,2
Marcello Coreno,3 Monica de Simone,4 Cesare Grazioli,4,5 Malgorzata Biczysko,6,7 and
Alberto Baiardi.7
1
School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road,
Edinburgh EH9 3FJ, Scotland, UK
2
ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-
8000 Aarhus C, Denmark
3
CNR-IMIP, Montelibretti, c/o Laboratorio Elettra, Trieste, Italy
4
CNR-IOM Laboratorio TASC, Trieste, Italy
5
Department of Chemical and Pharmaceutical Sciences, University of Trieste, Italy
6
National Research Council ICCOM-CNR, UOS di Pisa, Via G. Moruzzi 1, I-56124 Pisa,
Italy
7
Scuola Normale Superiore, Piazza Cavalieri 7, 56126 Pisa, Italy
Email:m.h.palmer@ed.ac.uk;
nykj@phys.au.dk;
tr01@staffmail.ed.ac.uk;
vronning@phys.au.dk;
marcello.coreno@elettra.eu;
desimone@iom.cnr.it;
malgorzata.biczysko@sns.it
Phonea: +44 (0) 131 650 4822
Contents:
SM1. Further details of the PES study................................................................................... 2
SM2. Basis sets and CI procedures ........................................................................................ 2
SM3. Ground, excited singlet and ionic structural differences .......................................... 3
SM4. Franck-Condon ionic state calculated frequencies and intensities............................ 3
=================================================================
2
SM1. Further details of the PES study
The full spectrum, recorded using 95 eV photons, covers the range 7.5 to 89.5 eV with
a resolution of ~0.025 eV. The region from 8-32 eV is shown in Fig. S1, which includes the
Tamm-Dancoff approximation (TDA) pole strengths, using a logarithmic scale to enhance the
intensity of the higher energy region. The TDA calculated values above 12 eV show
progressively higher energy than observed, but the main features of the PES are demonstrated.
In Fig. S1, the divergence of the theoretical and observed spectra can be removed and a tight
fit obtained using IEObs = a + b*IECalc, when a = 1.5(2) and b = 0.87(14). The magnitude of the
intercept is surprisingly large, but the slope of the correlation is in line with usual correlations
over a wide energy range. The spectral profile is similar to previous HeII (40.3 eV) spectra;1 A
comparison of the outer valence shell PES with calculated Green’s Function (GF) values is
shown in Table S1.
The high resolution data (experimental resolution ~8 meV) was converted to IE by fitting
the PES spectral profile to a set of Gaussian functions, as shown in Fig. S2 for IE1; similar
approaches were applied to IE2 to IE4. The near identity of the fit (bottom) to the observed
spectrum (middle), with small residuals (top) is demonstrated. However, the residuals show a
significant vibrational structure, which is a result of the asymmetric structure of each
vibrational band, owing to the underlying sequence bands.
SM2. Basis sets and CI procedures
Compared with C and H atoms, there are relatively few ab initio basis sets for the Iatom.2,3 We found the Sadlej4 p-VTZ I atom basis set ([11s8p6d2f] contracted functions)
suitable in combination with the C and H atom bases TZVP5 and aug-cc-pVTZ.6 However, in
several ionic state equilibrium structure searches, this led to saddle points rather than genuine
minima at both the MCSCF and UHF theoretical levels. The effective core potential (ECP)
quasi-relativistic basis sets, including CRENBL7 and SDD8 (Stuttgart potentials for Z > 2,
equivalent to cc-pVDZ), gave genuine minima for these cases, in the UHF method. A
significantly smaller basis set, SNSD, in conjunction with the B3LYP functional, has been
applied for VPT2 computations in the ground state. The double- SNSD basis set9 is an
improved version of the (polarized DZ) N07D basis set10-13 obtained by adding diffuse sfunctions on all atoms, diffuse polarized d-functions on heavy atoms (p on hydrogens) and
Stuttgart-Dresden electron core pseudopotentials8 to bromine and iodine. This basis set has
3
shown a very good performance for anharmonic corrections to frequencies and IR intensities
for a series of halogenated organic compounds.14
SM3. Ground, excited singlet and ionic structural differences
Despite inclusion of data from natural abundance
13
C isotopomers, the gas-phase
molecular structure of PhI is incomplete; the microwave (MW) spectral,15-18 electron
diffraction (ED)19 and nematic phase NMR studies,20,21 all made assumptions for some
geometric parameters. A comparison of the microwave and nematic phase data with the
equilibrium structure using MCSCF methods is shown in Fig. S3. The MW+ED results are
average C-C bond lengths; the nematic phase NMR results assume two bond lengths.
At the MCSCF level the X2B1 and A2A2 states are almost unchanged from the neutral
ground state, while for the B2B2 state, C-I lengthens (+0.07 Å), with minor changes elsewhere
as shown in Fig. S4. These relatively small differences from the neutral ground state are
consistent with a high 0-0 band in the PES. The C2B1 state shows considerable differences from
the lower X2B1 states, with substantial lengthening of the C2,3 bond. The D2A1 state dissociates,
as mentioned above.
SM4. Franck-Condon calculated ionic state frequencies and intensities
The principal vibrations excited in the cold band structure, obtained using the B3LYP
method with the Sadlej (iodine) + aug-cc-pVTZ (C+H) basis are shown in Table S2.
References
1
D. M. P. Holland, D. Edvardsson, L. Karlsson, R. Maripuu, K. Siegbahn, A. W. Potts, and
W. von Niesson, Chem. Phys. 253, 133 (2000).
2
D. Feller, J. Comp. Chem. 17, 1571,(1996).
3
K. L. Schuchardt, B. T. Didier, T. Elsethagen, L. Sun, V. Gurumoorthi, J. Chase, J. Li, and
T. L. Windus, J. Chem. Inf. Model. 47, 1045 (2007).
4
A. J. Sadlej, Theo. Chim. Acta 81, 339 (1992).
5
A. D. McLean and G. S. Chandler, J. Chem. Phys. 72, 5639 (1980).
6
T.H. Dunning, J. Chem. Phys. 90, 1007 (1989).
7
L. A. Lajohn, P. A. Christiansen, R. B. Ross, T. Atashroo, and W. C. Ermler, J. Chem. Phys.
87, 2812 (1987).
4
8
G. Igel-Mann, H. Stoll, and H. Preuss, Mol. Phys. 65, 1321 (1988).
9
Double and triple-f basis sets of SNS and N07 families are available for download, 2012.
http://compchem.sns.it> (accessed 01.11.2014)
10
V. Barone, P. Cimino, and E. Stendardo, J. Chem. Theory Comput. 4, 751 (2008).
11
V. Barone and P. Cimino, Chem. Phys. Lett. 454, 139 (2008).
12
V. Barone and P. Cimino, J. Chem. Theory Comput. 5, 192 (2009).
13
V. Barone, J. Bloino, and M. Biczysko, Phys. Chem. Chem. Phys. 12, 1092 (2010).
14
I. Carnimeo, C. Puzzarini, N. Tasinato, P. Stoppa, A. P. Charmet, M. Biczysko, C. Cappelli,
and V. Barone, J. Chem. Phys. 139, 074310 (2013).
15
A. M. Mirri and W. Caminati, Chem. Phys. Lett. 8, 409 (1971).
16
O. Dorosh, E. Bialkowska-Jaworska, Z. Kislel, and L. Pszczolkowski, J. Mol. Spectrosc.
246, 228 (2007).
17
K. C. Etchison, C. T. Dewberry, K. E. Kerr, D. W. Shoup, and S. A. Cooke, J. Mol. Spectrosc.
242, 39 (2007).
18
J. L. Neill, S. T. Shipman, L. Alvarez-Valtierra, A. Lesarri, Z. Kisiel, and B. H. Pate, J. Mol.
Spectrosc. 269, 21 (2011).
19
J. Brunvoll, S. Samdal, H. Thomassen, L. V. Vilkov, and H. V. Volden, Acta Chem. Scand.
44, 23 (1990).
20
J. Jokisaari, T. Vaananen, and J. Lounila, Mol. Phys. 45, 141 (1982).
21
R. Ugolini and P. Diehl, J. Mol. Struct. 216, 325 (1990).
Table S1.
The experimental IEs and values calculated using the GF method.a
Exp. IEb
/ eV
GF Calc. Energyc
/ eV
Pole
strength
Leading term
vacancy
8.654
9.523
9.868
10.564
11.554
12.385
12.586
13.609
14.369
15.018
15.529
16.702
18.679
8.669
9.466
9.621
10.497
11.639
12.526
13.044
13.894
14.845
15.397
15.648
17.297
19.561
0.902
0.890
0.912
0.894
0.901
0.896
0.812
0.882
0.879
0.856
0.867
0.840
0.178
3b1-1
1a2-1
6b2-1
2b1-1
8a1-1
5b2-1
1b1-1
7a1-1
4b2-1
3b2-1
6a1-1
5a1-1
4a1-1
Calc. state
symmetry
2
B1
A2
2
B1
2
B1
2
A1
2
B1
2
B1
2
A1
2
B1
2
B1
2
A1
2
A1
2
A1
2
State
symbol
X
A
B
C
D
E
F
G
H
I
J
K
L
5
2
19.120
20.304
0.740
2b2-1
B1
M
a
1
Holland et al. give the same symmetry sequence from ADC(3) calculations
b
Vertical except for IE1 to IE4.
c
6-3111G** basis, using active MOs from the valence shell with sequence nos. 30 to 179
Table S2.
Principal vibrations of the first four ionic states excited in the PES of PhI.
Energy /
cm-1
0
290
581
871
1060
1161
1350
1596
1641
1886
1932
2177
X2B1
Intensity / 104
dm3 mol-1 cm-1
4.76
5.79
3.69
1.65
1.27
0.58
1.71
0.61
1.18
0.77
0.57
0.52
Energy /
cm-1
0
276
551
668
944
994
1028
1270
1303
1336
1560
1662
1696
1836
A2A2
Intensity / 104
dm3 mol-1 cm-1
2.49
1.38
0.39
1.32
0.69
0.53
0.53
0.29
0.28
0.34
0.45
0.28
0.29
0.25
Assignment
00
111
112
113
71
114
71111
41
1
7 112
41111
71113
41112
Assignment
00
111
112
101
101111
91
81
91111
81111
102
41
91101
81101
41111
Energy /
cm-1
0
670
1027
1339
1697
B2B2
Intensity / 104
dm3 mol-1 cm-1
7.22
1.70
1.01
0.28
0.22
Energy /
cm-1
0
234
468
671
905
1049
1139
1283
1342
1576
X2B1
Intensity / 104
dm3 mol-1 cm-1
7.30
6.15
2.21
2.75
2.00
0.59
0.56
0.47
0.54
0.32
Assignment
00
101
91
102
91101
Assignment
00
111
112
101
101111
81
101112
81111
102
102111
6
Figure S1.
The wide scan photoionization of PhI obtained by irradiation at 95 eV. The
TDA calculated pole strengths, using a logarithmic scale to enhance the intensity of the higher
energy region, are superimposed.
7
Figure S2.
Deconvolution of the X2B1 PES profile.
8
Figure S3
The combined analysis of the MW and ED structures compared with the
MCSCF and TDDFT equilibrium structures of PhI.
9
Figure S4
Ionic state equilibrium structures