Structure and excitedstate dynamics of the S 1

Structure and excited-state dynamics of the S 1 B 3 u‐S 0 Ag states of pyrene through high-resolution laser spectroscopy Yasuyuki Kowaka Kyoto University

Excited-state Dynamics Predissociation IC S 2 S 1 ISC IVR T 1 abs. S 0 fluo. phos.

This Work IC Ultrahigh-resolution spectrum Electronic structure of S 1 Accurate molecular constants Theoretical calculation Molecular structure ISC Ultrahigh-resolution spectrum in magnetic field of 1. 2 Tesla IVR Dispersed fluorescence spectrum

Pyrene (C 16 H 10) E C 2 (z ) C 2 (x ) C 2 (y ) i σxy σyz σzx Ag 1 1 1 1 B 1 g 1 1 -1 -1 R(z) B 2 g 1 -1 R(x) B 3 g 1 -1 -1 1 R(y) Au 1 1 -1 -1 B 1 u 1 1 -1 -1 1 1 z B 2 u 1 -1 -1 1 x B 3 u 1 -1 -1 1 1 -1 y

Vibrational Spectra Dispersed fluorescence spectrum fluorescence excitation spectrum

Results of Vibronic Transition of Pyrene • ag vibronic transition (B-type) ← Franck-condon Factor • b 1 g vibronic bands (A-type) seen in the spectrum ← S 1 -S 2 Vibronic Coupling • Fluorescence lifetime in the S 1 state is long (1400 ns). • Vibrational structures in the S 0 and S 1 states are similar.

Observation of Ultrahigh-Resolution Spectrum Etalon Marker Nd YVO 4 Laser Ref: I 2 absorption Ring Ti: S Laser skimmer, φ2 mm Ar + sample Magnet Pulse nozzle Computer 150 ℃ slit, width 2 mm Photon counter UV PM

Ultrahigh-Resolution Spectrum of Pyrene

Assignment of Pyrene

Band of Pyrene Calculated Observed -1 Cm

Rotational Constants A B C S 0 （10 -2 cm-1）a) 3. 38922 1. 86601 1. 20343 S 1 （10 -2 cm-1）b) 3. 36282 1. 85299 1. 19469 A B C S 0 （10 -2 cm-1） 3. 39147 1. 86550 1. 20406 S 1 （10 -2 cm-1） 3. 36223 1. 84864 1. 19329 Calc. a) cisd/4 -31 g b) TDDFT/cam-b 3 lyp/6 -31 g（d, p） Expt. Moment of inertia defect ｜Ic－Ia－Ib｜ ≪ Ic Both in the S 0 and S 1 states

Ab initio Calculation of Excited State Ground State ΔSCF Excited State TDDFT

Results of Theoretical Calculation　in the S 1 state A B C 3. 36223 1. 84864 1. 19329 3. 36282 1. 85299 1. 19469 3. 35556 1. 84965 1. 19239 3. 41668 1. 84011 1. 19599 3. 34650 1. 84267 1. 18834 3. 36785 1. 81527 1. 17952 3. 41973 1. 84529 1. 19855 CIS/cc-pvtz 3. 43928 1. 86073 1. 20747 SAC-CI/6 -31 g(d, p) 3. 39482 1. 84273 1. 19402 Expt. TDDFT CAM-B 3 LYP/ 6 -31 G(d. p) TDDFT WB 97 XD/ 6 -31 G(d. p) TDDFT B 2 PLYPD/ 6 -31 G(d. p) TDDFT WB 97 XD/ cc－pvdz TDDFT B 3 LYP/ 6 -31 G CIS/6 -31 G （d. p） In the unit of 10 -2 cm-1

Internal Conversion Rate Fermi’s golden rule Non-adiabatic Franck-Condon Overlap WIC depends on these vibrational overlaps.

Contribution to Internal Conversion IC is very slow in the S 1 state of pyrene

Ultrahigh Resolution Spectrum in Magnetic Field H= 1. 2 T H= 0 Relative Energy

Remarkable Radiationless Transition in the Vibronic Levels Graph of fluorescence lifetime (ns) vs. energy relative to the S 1 origin at 27216 cm-1. The circles represent the lifetime after excitation into a distinct line of the spectrum, while the squares designate values measured after excitation into the surrounding background. J. Phys. Chem. , 1986, 90 (5), Elisa A. Mangle and Michael R. Topp

Dispersed Fluorescence Spectra indicates IVR

Conclusions • ISC to T state is very slow • IC to S 0 state is very slow • Predissociation doesn’t occur Florescence lifetime is very long in the S 1 state • IVR occurs above 730 cm-1

Results of Theoretical Calculation　in the S 0 state A B C Expt. 3. 39147 1. 86550 1. 20406 CISD/4 -31 G 3. 38923 1. 86601 1. 20344 CISD/6 -31 G 3. 36951 1. 85543 1. 19655 MP 2/cc-pvtz 3. 38767 1. 86436 1. 20255 MP 2/6 -31 G(d, p) 3. 37187 1. 85546 1. 19686 HF/cc-pvtz 3. 42150 1. 88645 1. 21600 HF/6 -31 G(d, p) 3. 40455 1. 87666 1. 20979 DFT/cc-pvtz 3. 39412 1. 86518 1. 20370 3. 36913 1. 85139 1. 19482 DFT/6 -31 G(d, p) In the unit of 10 -2 cm-1

The Change of the Molecular Structure upon Electronic Excitation Angle (°) 1. 3478 1. 3730 the S 0 state +0. 12 1. 4169 1. 4498 the S 1 state in the unite of Bond length (Å) 1. 4319 1. 3857 +0. 63 1. 4448 1. 4233 +0. 59 1. 3960 1. 4037 +0. 53 1. 4015 1. 3883

i) To identify electric structure of S 1 Observation of LIF Excitation Spectrum laser ray photon counter carrier gas chamber PM dye laser pump laser computer fluorescence laser intensity plot molecular beam

i) To identify electric structure of S 1 Observation of Dispersed Fluorescence Spectrum Laser ray photon counter fluorescence dye laser computer pump laser monochromator carrier gas chamber PM laser intensity plot molecular beam

Excitation Fluorescence Spectra

Configuration Interaction(CI) LUMO+1 CI LUMO HOMO-1 1 La 1 Lb has much smaller Transition Intensity than 1 La. S : long fluorescenece lifetime(about 1. 4 μs) 1 S 2 S 1

A part of Assignment of Vibration Scaling factor 　　　　 0. 9830 　 0. 8930

Rotational Envelopes Useful to distinguish between ag bands and b 1 g bands A-type B-type A-type 00 0

Direction of the Transition Moment A type ΔKa = 0, ± 2, ・・・ ΔKc = ± 1, ± 3, ・・・ Ka. Kc = ee-eo , oo-oe B type ΔKa = ± 1, ± 3, ・・・ ΔKc = ± 1, ± 3, ・・・ Ka. Kc = ee-oo , eo-oe C type ΔKa = ± 1, ± 3, ・・・ ΔKc = 0, ± 2, ・・・ Ka. Kc = ee-oe , oo-eo

Rotational Envelopes

Excitation spectra of Pyrene-h 10 and Pyrene-d 10 H 10 D 10