ULTRAHIGH-RESOLUTION SPECTROSCOPY OFDIBENZOFURAN S1←S0 TRANSITIONSHUNJI KASAHARA1, Michiru Yamawaki1, and Masaaki Baba21) Molecular Photoscience Research Center, Kobe University, Japan2) Graduate School of Science, Kyoto University, Japan
J
K
c(z)
J
Kc
c
a
oblate symmetric top
A=B>C
b(z)
near prolate asymmetric top
A>B~C
J
Kc
a(z)
b
c
Motivation for the Measurement of Excited Statesby Doppler-Free / Sub-Doppler High Resolution Spectroscopy
Rotational-resolved high-resolution spectrum in UV-VIS region
Regularity
of rotational lines
Molecular constants
in high accuracy
Anomalies
of rotational lines
Line position (energy shift)
Line width (broadening)
Zeeman effect (splitting)
Assignments of rotational transitions
Molecular structure
Dynamical process
Nd:YVO4 Laser; Millenia Xs
Magnet
Ar gas
Pulse
nozzle
Sample
Filter
UV laser
Etalon marker
PD
I2 cell
Lock-in Amp.
EOM
PD
Skimmer
Slit(1 mm)
Vac. pump
Vac. pump
PM
Ring Dye Laser; CR699-29
UV Laser Molecular Beam
Single-mode Laser
Absolute Wavenumber Measurement System
Doubling Cavity;WavetrainSC
Computer
Computer
Photon Counter
Accuracy 0.0001 cm-1
0.0001 cm-1
Ultrahigh-resolution UV spectroscopy in molecular beam
Liq. N2
Trap
(FWHM) 0.0005 cm-1
Etalon
PBS
PD
λ/4
PZT
YAG Laser
Error Signal Generator
19MHz Oscillator
EOM
PBS
Error Signal Generator
19MHz Oscillator
I2 stabilized
YAG laser
I2 Cell
PD
PBS
PC
Stabilized
Etalon
EOM
PD
Laser
EOM
30MHz Oscillator
Frequency Marker (each 30 MHz)
Nd:YVO4 Laser; Millenia Xs
Magnet
Ar gas
Pulse
nozzle
Sample
Filter
UV laser
Etalon marker
PD
I2 cell
Lock-in Amp.
EOM
PD
Skimmer
Slit(1 mm)
Vac. pump
Vac. pump
PM
Ring Dye Laser; CR699-29
UV Laser Molecular Beam
Single-mode Laser
Absolute Wavenumber Measurement System
Doubling Cavity;WavetrainSC
Computer
Computer
Photon Counter
Accuracy 0.0001 cm-1
0.0001 cm-1
Ultrahigh-resolution UV spectroscopy in molecular beam
Liq. N2
Trap
(FWHM) 0.0005 cm-1
Chopper
PBS: Polarization
Beam splitter
I2 Cell
PBS
PBS
Laser
Photo
-diode
Photo
-diode
Doppler-free absorption spectrum of I2
Absolute wavenumber of each I2 hyperfine line can be obtained from
“Doppler-free High Resolution Spectral Atlas of Iodine Molecule 15000 to 19000 cm-1”
in accuracy of 0.0001 cm-1.
Nd:YVO4 Laser; Millenia Xs
Magnet
Ar gas
Pulse
nozzle
Sample
Filter
UV laser
Etalon marker
PD
I2 cell
Lock-in Amp.
EOM
PD
Skimmer
Slit(1 mm)
Vac. pump
Vac. pump
PM
Ring Dye Laser; CR699-29
UV Laser Molecular Beam
Single-mode Laser
Absolute Wavenumber Measurement System
Doubling Cavity;WavetrainSC
Computer
Computer
Photon Counter
Accuracy 0.0001 cm-1
0.0001 cm-1
Ultrahigh-resolution UV spectroscopy in molecular beam
Liq. N2
Trap
(FWHM) 0.0005 cm-1
PM
Magnet
Laser
A
A
B
B
Skimmer
Pulse nozzle
Sample
Pole peace
Pole peace
Slit
Molecular Beam
Liq. N2trap
Liq. N2trap
Marker etalon (stabilized by I2 stabilized YAG laser)
Doppler-free absorption spectrum of I2
Rotational-resolved high-resolution spectrum of Dibenzofuran
Ultrahigh-resolution spectrum of 000+ 443 cm-1 band
S1←S0 spectrum of dibenzofuran in a molecular beam (resolution : 0.2 cm-1)
dibenzofuran
Ultrahigh-resolution spectrum of 000 and 000 + 443 cm-1 band
B-type transition
A-type transition
Ψ47
B1
Ψ46
Ψ45
Ψ44
A2
B1
A2
Ψ43
B1
Ψ42
A2
HOMO
LUMO
2nd LUMO
2nd HOMO
34087(+443 cm-1)
1A1
1A1 ( S0 )
1B2 ( S2 )
1A1 ( S1 )
Hvibronic
A-type
ΔKa = 0
B-type
ΔKa =±1
E (cm-1)
0
33644
41000
HOMO－LUMO
Electronic excited states of dibenzofuran molecule
y(a)
z(b)
O
Ultrahigh-resolution spectrum of 000 and 000 + 443 cm-1 band
Ultrahigh-resolution spectrum of 000 band (P lines)
Obtained Molecular Constants of S1 and S0 States of dibenzofuran
S0 1A1 (v=0)
S1 1A1 (v=0)
A (cm-1)
0.0759913(10)
0.07527912(81)
B
0.02005071(65)
0.01982969(29)
C
0.01586638(57)
0.01569587(17)
DK (×10-8)
3.67(22)
3.33(19)
DJK (×10-8)
-3.43(15)
-3.328(70)
DJ (×10-9)
5.20(27)
5.374(88)
δK (×10-7)
3.26(11)
3.106(21)
δJ (×10-9)
1.79(13)
2.102(49)
κ
-0.86091
-0.86124
Ia (×10-46 kg m2)
36.83678
37.18528
Ib
139.60976
141.16584
Ic
176.42807
178.34467
⊿ = Ic- Ia- Ib
-0.01847
-0.00644
T0 (cm-1)
-
33644.347663(66)
standard deviation
-
0.00059
fitted lines
-
4835 lines
assigned lines
-
5032 lines
band type
-
B type
Ultrahigh-resolution spectrum of 000 and 000 + 443 cm-1 band
Ultrahigh-resolution spectrum of 000 + 443 cm-1 band (Q lines)
S1←S0 spectrum of dibenzofuran in a molecular beam (resolution : 0.2 cm-1)
dibenzofuran
Ultrahigh-resolution spectrum of higher vibrational band
Obtained Molecular Constants of S1 and S0 States of dibenzofuran
S0 1A1 (v=0)
S1 1A1 (v=0)
S1 1A1 (b2:v55=1)
(000 + 443 cm-1)
S1 1A1
(000 + 857 cm-1)
S1 1A1
(000 + 1149 cm-1)
S1 1A1
(000 + 1321 cm-1)
A (cm-1)
0.0759913(10)
0.07527912(81)
0.07509478(55)
0.07520210(95)
0.0750354(15)
0.0745546(53)
B
0.02005071(65)
0.01982969(29)
0.01985611(25)
0.01983592(28)
0.0198581(50)
0.01987367(51)
C
0.01586638(57)
0.01569587(17)
0.01571066(20)
0.01570413(15)
0.01570651(27)
0.01571172(26)
DK (×10-8)
3.67(22)
3.33(19)
3.24(12)
3.12(20)
-
2.81(41)
DJK (×10-8)
-3.43(15)
-3.328(70)
-3.099(58)
-3.224(71)
-
-1.099(78)
DJ (×10-9)
5.20(27)
5.374(88)
4.826(82)
5.763(61)
-
5.83(21)
δK (×10-7)
3.26(11)
3.106(21)
2.976(27)
3.474(16)
-
2.830(52)
δJ (×10-9)
1.79(13)
2.102(49)
1.628(57)
1.964(34)
-
2.24(12)
κ
-0.86091
-0.86124
-0.86039
-0.86111
-0.86005
-0.85854
Ia (×10-46 kg m2)
36.83678
37.18528
37.27656
37.22336
37.30606
37.54664
Ib
139.60976
141.16584
141.97801
141.12150
140.96388
140.85344
Ic
176.42807
178.34467
178.17678
178.25087
178.22386
178.14676
⊿ = Ic- Ia- Ib
-0.01847
-0.00644
-0.07778
-0.09399
-0.04608
-0.23532
T0 (cm-1)
-
33644.347663(66)
34087.498758(52)
34501.877194 (82)
34794.46442(13)
34965.918929(98)
standarddeviation
-
0.00059
0.00034
0.00054
0.00068
0.0010
fitted lines
-
4835 lines
2904 lines
2449 lines
135 lines
999 lines
assigned lines
-
5032 lines
3047 lines
2529 lines
140 lines
1048 lines
band type
-
B type
A type
A type
A type
A type
Zeeman broadening of 000 band
ZS∝Kc2
ZS∝J
2
Kc = 0
（Ka =J ）
Kc = J
（Ka =0 ）
J
c
Kc
a
m
Magnetic moment is along to c-axis.
(out of plane)
(J, K) dependence of the observed Zeeman splittings
ZS
-MJ
MJ
J
K
c(z)
J
Kc
a
b(z)
J
Kc
a(z)
b
Zeeman interaction
c(y)
c(x)
All these molecule,
(i) the order of magnitude of Zeeman Splitting is the same.
(ii) the J- and K-dependences are the same. ZS ∝ (Kc)2, ZS ∝ J
Magnetic moment is along to c-axis. (out of plane)
The magnetic moment comes from the orbital angularmomentum of electrons, not from the triplet state!
Rotationally resolved ultrahigh-resolution spectra of jet-cooled dibenzofuran(DF) for the 000 and several vibronic bands up to 000 + 1335 cm-1 band have beenobserved. Several thousand lines were assigned and these molecular constantswere determined.
The S1 state is assigned to be the 1A1 ( *) state. The intensity arises from thevibronic coupling with the S2 1B2 state.
The Zeeman broadenings of the rotational lines were also observed, and the J,K-dependence were studied. As a result, the observed Zeeman effects could beexplained to be originating from the magnetic moment of the S1 1A1 stateinduced by mixing with S2 1B2 state by J-L coupling, which suggests thatrotationally resolved levels are not mixed with a triplet state largely.
Summary
Thank you for your attention !
band
+443 cm-1 band
A type
ΔKa = 0, ±2, ・・・
ΔKc = ±1,±3, ・・・
B type
ΔKa =±1,±3, ・・・
ΔKc = ±1,±3, ・・・
C type
ΔKa = ±1,±3,・・・
ΔKc = 0, ±2,・・・
J
c
Kc
a
b
Ka
ΔJ = －1, 0, 1
Calculated spectrum of 000 band
S1←S0 and S2←S0 spectrum of dibenzofuran in a molecular beam (resolution : 0.2 cm-1)
S1←S0
S2←S0
Ultrahigh-resolution spectrum of 000 + 443 cm-1 band (P lines)
Doppler-free absorption spectoroscopy
of iodine molecule
Chopper
PBS: Polarization
Beam splitter
I2 Cell
PBS
PBS
Laser
Photo
-diode
Photo
-diode
CW single-mode dye laser
Single mode
UV laser beam
Doubling cavity