Supplementary Materials: (JCP)
Conical intersection seam and bound resonances embedded in continuum
observed in the photodissociation of thioanisole-d3
Songhee Han, Jeong Sik Lim, Jun-Ho Yoon, Jeongmook Lee, So-Yeon Kim, and Sang Kyu Kim*
Department of Chemistry, KAIST, Daejeon (305-701), Republic of Korea
Materials and Methods:
Resonance-enhanced two- photon ionization (R2PI) spectroscopy , photofragment excitation
(PHOFEX) spectroscopy and velocity map ion imaging
Thioanisole (C6H5SCH3, Aldrich, 99%) and thioanisole-d3 (C6H5SCD3, custom-made) seeded
in the He carrier gas were prepared in a supersonic jet with a backing pressure of ~ 3
atmosphere. The sample was heated to 35 °C. The pulsed nozzle valve (General Vale 9
series, 0.5 mm diameter) was operated at a repetition rate of 10 Hz. For the R2PI and
PHOFEX experiments, the excitation pump laser pulses were generated by a Nd:YAG
pumped dye laser (Sirah, Cobrastretch series). The dye laser output (Δt ~ 5 ns) was
frequency-doubled using a beta-barium-borate (BBO) crystal mounted on a homemade auto
tracker. In order to obtain the PHOFEX spectrum, a probe laser pulse generated by another
independently tunable dye laser (Lambda Physik, Scanmate 2) was used to ionize the
nascent ·CD3 fragment using the Q transition to the zero point level (000 ) of the 3p 2A2"
Rydberg state. For the kinetic energy and angular distribution measurements of the ·CD3
fragment, the velocity-map ion imaging technique was employed.S1 Images were averaged
for 500,000 ~ 720,000 laser shots. Polarizations of both pump and probe laser pulses were
perpendicular to the flight direction of the ion and parallel to the plane of the positionsensitive detector. The raw images were reconstructed using the BASEX algorithm.S2
1
(1+1’) Mass analyzed threshold ionization (MATI ) spectroscopy
Detailed experimental methods were described in Refs. S2-S3. Two counterpropagating laser pulses were overlapped with a molecular beam for the (1+1’) MATI
experiment. Long-lived high-n,l Rydberg states prepared using various S1 intermediate
vibronic states were ionized with a pulsed electric field of ~ 160 V/cm after the delay time of
~ 50μs, which was long enough for the separation of the MATI signal from the directly
formed ions. The ion species generated by the pulsed electric field were accelerated, drifted
along the time-of-flight axis and were detected by dual microchannel plates (MCP). Ion
signals were digitized using an oscilloscope (LeCroy, LT584M) and stored in a personal
computer. For the analysis of the MATI spectra, the minimum energy structure and normal
modes were calculated using the B3LYP density functional theory (DFT) with a basis set of
6-311G++(3df,3pd). The vibronic bands appeared in the R2PI spectra were appropriately
assigned based on the propensity and symmetry selection rules.
Computational details
Four structural parameters, d(C-SCD3), d(CS-CD3), (C-S-CD3), and (S-C-D(3)) were selected
to locate the S1/S2 conical intersection seam in the reduced dimensionality (Table 1). The S1/S2
minimum energy conical intersection (MECI) was obtained by full optimization. Potential
energy curves along each coordinate were calculated at the level of a state-averaged
complete active space self-consistent field (SA-CASSCF)S5-S6 with an active space associated
with 12 electrons distributed into 11 molecular orbitals (MOs) using a 6-311++G(d,p) basis
set (Table S1). Second- order multireference perturbation theory (CASPT2)S7 was used for the
calculation of some selected energy points in Table 1. Potential energy curves obtained by
varying the d(CS-CD3) and (S-C-D(3)) values gave two S1/S2 degenerate points (Fig. S4A).
The relatively low- (seam-L) or high-lying (seam-H) S1/S2 degenerate points were obtained
by varying of the d(CS-CD3) or (S-C-D(3)) values while the other three parameters were
optimized. The S1/S2 degenerate points between seam-L and seam-H could then be obtained
at fixed values of d(CS-CD3) and (S-C-D(3)) by varying the other two parameters for the
optimization. Consequently, the S1/S2 conical intersection seam was generated so that it
2
could be depicted in the two-dimensional d(CS-CD3)-(S-C-D(3)) coordinates as a line
connecting degenerate points for which the S1 and S2 energy difference was calculated to be
less than 5 cm-1 (Fig. 4). Gradient difference (g) and nonadiabatic coupling (h) vectors for the
degenerate points on the seam and for MECI were calculated using the coupled-perturbed
multi-configurational self-consistent field (CP-MCSCF) method. S5-S6
D0 normal modes of thioanisole and thioanisole-d3 were calculated at the B3LYP
(DFT)/6-311++G(3df,3pd) or SA4-CASSCF(11,11)/6-311++G(d,p) level. The displacement
vectors of the vibrational modes obtained from the two methods were quite similar while
associated vibrational energies were somewhat different. Vibrational frequencies in the
MATI spectra were assigned based on the DFT calculation (Table S2). The nuclear
configurations spanned by the normal modes, as can be seen in Fig. 4 and Fig. S4, are those
obtained from the CASSCF calculation.
The nuclear configurations spanned by the linear
combination of three normal modes with variable weighting factors are shown in Fig. S6.
Potential energy curves along several D0 normal modes calculated at the CASSCF(12,11)/6311++G(d,p) level, are shown in Fig. S7. All CASSCF and DFT calculations were performed
with MOLPRO (version 2010.1)S8 and the Gaussian 09 program package,S9 respectively.
3
Supplementary figures
Fig. S1. Total translational energy distributions (P(E)) deduced from nascent CD3+ images at
excitation energies of (A) 34,515 cm-1 and (B) 35,606 cm-1. Corresponding raw (left) and
~
~
reconstructed (right) images are given in the inset. Distribution is deconvoluted into A , X ,
and background channels as denoted by dotted lines of red, blue, and green, respectively.
4
Fig. S2. (A) R2PI spectra of thioanisole and (B) thioanisole-d3 with vibrational assignments
obtained from the analysis of the MATI spectra. Nuclear displacement vectors of some
normal modes are depicted.
5
Fig. S3. (A) MATI spectra of thioanisole and (B) thioanisole-d3. The S1 excitation energy used
as an intermediate state in each (1+1′) MATI spectrum is indicated. Assignments of MATI
spectra are summarized in Table S2.
6
Fig. S4. (A) Conical intersection seam is plotted along the CS-CD3 bond length and S-C-D(3)
bending angle. Empty triangles (black line), circles (red line) and squares (blue line) indicate
S0, S1 and S2 states, respectively. Filled circles (magenta) are electronically degenerate points
(seam) of the S1 and S2 states. A filled star (green) represents MECI. Nuclear configurations
spanned by several normal modes of (B) thioanisole-d3 and (C) thioanisole are represented
in three different coordinates to be compared with the calculated conical intersection seam
(magenta filled circles). Filled triangles (black line), filled squares (red line), filled pentagons
(blue line), empty squares (green) and empty triangles (orange) indicate νs+, 7a+, βasCH(D)3+,
15+ (phenyl moiety deformation), and 6b+ (C-S-CH(D)3 bending) modes, respectively.
Fig. S5. g and h vectors at MECI and two different molecular structures (seam-L and seam-H)
on the seam are shown (see the text for details)..
7
Fig. S6. Nuclear configurations spanned by nuclear displacement vectors constructed using
the linear combinations of νs+, 7a+, βasCD3+ normal modes with different weighting factors.
Filled triangles (black line), filled squares (red line), filled pentagons (blue line), empty
square (green) and empty triangles (orange) represent nuclear configurations obtained by
using weighting factors of (0.4, 0.6, 0), (0.9, 0, -0.1), (0, 0.7, 0.3), (0, 0.9, 0.1), (0.4, 0.5, 0.1) for
the (νs+,7a+, βasCD3+) modes, respectively.
8
Fig. S7. Theoretical results for thioanisole-d3 (A-C) and thioanisole(D-F). Potential energy
curves of S0, S1, S2 states are obtained along νs+(A, D), 7a+,(B, E), βasCD3+ (C, F) modes,
whereas these are depicted along one representative nuclear coordinate in the upper panel
of each figure. The corresponding nuclear configurations are given at the bottom.
9
Supplementary Tables
Table S1. Molecular orbital (MO) diagrams and associated occupation numbers (Occ.) of
four relevant neutral electronic states (S0, S1, S2, S3) and cationic ground state (D0) of
thioanisole-d3 obtained by SA4-CASSCF(12,11)/6-311++G(d,p) and SA4-CASSCF(11,11)/6311++G(d,p) calculations, respectively.
State
S0
S1
S2
S3
D0
0.03
0.03
0.04
0.03
0.02
0.03
0.03
0.04
0.04
0.03
0.04
0.10
0.10
0.06
0.04
0.1
0.52
0.11
0.12
0.08
0.1
0.61
1.00
0.83
0.09
MO
Occ.
10
1.90
1.40
1.00
1.20
1.01
1.90
1.50
1.89
1.89
1.90
1.96
1.87
1.90
1.93
1.92
1.97
1.97
1.96
1.96
1.96
1.98
1.98
1.97
1.96
1.97
1.99
1.99
1.98
1.97
1.98
11
Table S2. Experimental and calculated (S0, D0) vibrational frequencies (cm-1) of thioanisole
and thioanisole-d3. S0 and D0 frequencies were obtained from the B3LYP/6-311++G(3df,3pd)
level of calculation, whereas the values in parentheses were obtained using the SA4CASSCF(11,11)/6-311++G(d,p) calculation.
Thioanisole
mode*
symmetry
τ
a″
10b
a″
τCH3
a″
15
a′
βs
a′
16a
a″
6a
a′
16b
a″
6b
a′
4
a″
νs
a′
7a
a′
11
a″
10a
a″
γsCH3
a″
17b
a″
12 c
a′
βasCH3
a′
17a
a″
1
a′
S0†
D0†
48
95
(19)
(93)
168
156
(178)
(161)
230
184
(257)
(195)
196
191
(205)
(202)
332
340
(330)
(347)
412
384
(432)
(403)
420
434
(405)
(441)
485
438
(499)
(460)
631
598
(663)
(631)
700
645
(716)
(622)
698
688
(715)
(736)
729
734
(616)
(816)
754
780
(765)
(768)
850
831
(864)
(850)
972
934
(1007)
(999)
913
965
(922)
(963)
998
978
(1045)
(1033)
981
991
(1036)
(1055)
989
1015
(994)
(1023)
1045
1023
(1088)
(1075)
Thioanisole-d3
R2PI
MATI
mode*
symmetry
S0†
D0†
R2PI
MATI
37
89
τ
a″
45
(18)
88
(87)
35
87
66
150
10b
a″
195
(205)
167
(170)
178
τCD3
a″
142
(159)
122
(132)
63
124
200‡
15
a′
180
(189)
176
(186)
185
184
337
βs
a′
321
(319)
328
(336)
320
327
369
16a
a″
412
(431)
383
(403)
426
6a
a′
412
(397)
426
(434)
384
423
16b
a″
485
(499)
438
(460)
6b
a′
630
(663)
597
(630)
522
590
4
a″
699
(715)
645
(622)
204
392
524
589
687
690
νs
a′
666
(708)
657
(717)
656
664
724
732
7a
a′
714
(588)
727
(769)
705
726
11
a″
754
(765)
780
(768)
10a
a″
849
(864)
832
(851)
γsCD3
a″
734
(1009)
706
(1031)
17b
a″
913
(922)
965
(963)
12
a′
996
(1045)
980
(1033)
952
983
βasCD3
a′
775
(808)
778
(817)
755
775
17a
a″
989
(994)
1015
(1023)
1
a′
1045
(1087)
1022
(1073)
956
981
12
5
a″
18a
a′
18b
a′
9b
a′
9a
a′
14
a′
βsCH3
a′
3
a′
βsCH2
a′
19b
a′
γasCH3
a″
19a
a′
8b
a′
8a
a′
νsCH3
a′
νasCH2
a″
νasCH3
a′
20a
a′
7b
a′
13
a′
2
a′
20b
a′
1003
1029
(1011)
(1031)
1103
1103
(1144)
(1178)
1107
1123
(1153)
(1162)
1183
1192
(1217)
(1239)
1210
1222
(1277)
(1288)
1311
1318
(1325)
(1385)
1349
1360
(1460)
(1497)
1365
1372
(1436)
(1439)
1467
1453
(1556)
(1549)
1487
1458
(1604)
(1576)
1469
1460
(1590)
(1580)
1512
1488
(1614)
(1596)
1607
1546
(1667)
(1657)
1625
1604
(1723)
(1697)
3039
3052
(3197)
(3215)
3119
3147
(3294)
(3336)
3132
3155
(3282)
(3328)
3165
3190
(3313)
(3345)
3172
3197
(3320)
(3353)
3182
3207
(3333)
(3362)
3195
3215
(3345)
(3372)
3210
3225
(3365)
(3386)
5
a″
1003
(757)
1029
(745)
18a
a′
1103
(1149)
1104
(1186)
18b
a′
1107
(1151)
1121
(1168)
9b
a′
1183
(1217)
1192
(1239)
9a
a′
1210
(1277)
1222
(1288)
14
a′
1310
(1324)
1320
(1386)
βsCD3
a′
1034
(1096)
1030
(1186)
3
a′
1357
(1087)
1371
(1158)
βsCD2
a′
1075
(1556)
1050
(1549)
19b
a′
1468
(1164)
1454
(1139)
γasCD3
a″
1062
(1152)
1054
(1144)
19a
a′
1512
(1613)
1487
(1595)
8b
a′
1607
(1667)
1545
(1657)
8a
a′
1625
(1723)
1604
(1696)
νsCD3
a′
2176
(2288)
2184
(2299)
νasCD2
a″
2315
(2447)
2335
(2472)
νasCD3
a′
2321
(2435)
2340
(2479)
20a
a′
3165
(3313)
3190
(3345)
7b
a′
3172
(3320)
3197
(3353)
13
a′
3182
(3333)
3207
(3362)
2
a′
3195
(3345)
3215
(3372)
20b
a′
3210
(3365)
3225
(3386)
* Normal modes are labeled according to Refs. S10 and S11.
† The modes are listed in the increasing order of frequency value.
‡ This value is obtained from slow electron velocity imaging (SEVI) spectra.
§ The ring breathing motion of thioanisole is coupled to the CH3 wagging motion.
13
Table S3. Assignment of vibronic bands of thioanisole and thioanisole-d3 in the S1 electronic
state based on the analysis of (1+1’) MATI spectra. Unit is cm-1.
Thioanisole
Excitation
S1 internal
energy
energy
34 501
0 *, †,‡
34 575
Thioanisole-d3
Excitation
S1 internal
energy
energy
000
34 515
0 *,‡
000
74 †,‡
τ2
34 584
69 *,‡
τ2
34 633
132 †,‡
10b2
34 640
125 *,‡
τCD32
34 705
204 †,‡
151
34 667
152‡
τ1τCD32
34 717
216 †,‡
τ210b2 ||
34 700
185 *,‡
151
34 727
226 †,‡
τ6 ||
34 737
222 ‡
τ3τCD32
34 834
333 †,‡
βs1 ||, ¶
34835
320 ‡
β s1
34 906
405 *,†,‡
152
375 ‡
34 893
392 *,†,‡
6a1
34 890
34 899
384 *,‡
152
6a1
34 968
467 *,†,‡
τ26a1
34 970
455 ‡
τ26a1
35 025
35 096
524 *,‡
595 *,‡
6b
1516a1
35 037
35 085
522 *
570 *
6b1
1516a1
35 188
687 *,‡
ν s1
35 171
656 *,‡
ν s1
35 225
724 *,‡
7a1
35 220
705 *,‡
7a1
35 229
728 ‡
1516b1/τ1νs1
35 223
708 *,‡
1516b1/τ1νs1
35 283
782 *
6a2
35 283
768 *
6a2
35 413
912
6a16b1
35418
903
6a16b1
35 457
956 *
121
35 467
952 *,‡
121
35 845
1344 §
6a1121
35 851
1336
τ4τCD34121/6a
35 926
1425
τ26a1121
35939
1424
112
1 1
1/ν
τ26a112
s 6a2
Assignment
* These experimental values are assigned by using MATI spectroscopy
† These experimental values are assigned by previously reported ZEKE spectroscopy.S12
‡ These experimental values are assigned by SEVI spectroscopy.S12
§ The assignment of these experimental values are based on Ref. S12.
|| These assignments are different from those in ref. S12.
¶ A tentative assignment mode, νx, corresponds to the experimental value of 179 cm-1.
14
Assignment
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15
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16