ULTRAHIGH-RESOLUTION SPECTROSCOPY OF
DIBENZOFURAN S1←S0 TRANSITION
SHUNJI KASAHARA1, Michiru Yamawaki1, and Masaaki Baba2
1) Molecular Photoscience Research Center, Kobe University, Japan
2) Graduate School of Science, Kyoto University, Japan
JK
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 States by Doppler-Free / Sub-Doppler High Resolution Spectroscopy
Rotational-resolved high-resolution spectrum in UV-VIS region
Regularityof 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 structureDynamical process
Nd:YVO4 Laser; Millenia Xs
MagnetAr gas
Pulse nozzle
Sample
Filter
UV laser
Etalon marker
PD
I2 cell
Lock-in Amp.
EOMPD
Skimmer
Slit(1 mm)
Vac. pump Vac. pumpPM
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
EtalonPBS
PD λ/4 PZT
YAG Laser
Error Signal Generator
19MHz Oscillator
EOM
PBS
Error Signal Generator19MHz Oscillator
I2 stabilized YAG laserI2 Cell PD
PBS
PC
StabilizedEtalon
EOM
PD
LaserEOM
30MHz Oscillator
Frequency Marker (each 30 MHz)
Nd:YVO4 Laser; Millenia Xs
MagnetAr gas
Pulse nozzle
Sample
Filter
UV laser
Etalon marker
PD
I2 cell
Lock-in Amp.
EOMPD
Skimmer
Slit(1 mm)
Vac. pump Vac. pumpPM
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
PBSLaser
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
MagnetAr gas
Pulse nozzle
Sample
Filter
UV laser
Etalon marker
PD
I2 cell
Lock-in Amp.
EOMPD
Skimmer
Slit(1 mm)
Vac. pump Vac. pumpPM
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. N2 trap
Liq. N2 trap
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 00
0 + 443 cm-1 band
B-type transition
A-type transition
Ψ47B1
Ψ46
Ψ45
Ψ44
A2
B1
A2
Ψ43 B1
Ψ42 A2
HOMO
LUMO
2nd LUMO
2nd HOMO
34087(+443 cm-1)
0
1A1
1A1 ( S0 )
1B2 ( S2 )
1A1 ( S1 )
Hvibronic
A-typeΔKa = 0
B-typeΔKa =±1
1)( 255 b
E (cm-1)
0
33644
41000HOMO- LUMO
Electronic excited states of dibenzofuran molecule
y(a)
z(b)
O
Ultrahigh-resolution spectrum of 000 and 00
0 + 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 00
0 + 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
34964.0 34967.0 cm-1
00 + 1321 cm-1 band0
34792.0 34795.0 cm-1
00 + 1150 cm-1 band0
00 + 857 cm-1 band
34500.0 34503.0 cm-1
0
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)
standard deviation
- 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
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 angular
momentum 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 00
0 + 1335 cm-1 band have been
observed. Several thousand lines were assigned and these molecular constants
were determined.
The S1 state is assigned to be the 1A1 ( *) state. The intensity arises from the
vibronic 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 be
explained to be originating from the magnetic moment of the S1 1A1 state
induced by mixing with S2 1B2 state by J-L coupling, which suggests that
rotationally resolved levels are not mixed with a triplet state largely.
Summary
Thank you for your attention !
33641 33643 33645
33795.8507.14850D-02 1.59420D-02 1.30350D-026.94200D-02 1.58370D-02 1.30350D-02FWHM=0.007cm-1(210MHz)J<100, K<50
(b) B type
(c) C type
0 band
33641 33643 33645
cm-1
-1
-1
cm
cm
(a) A type
00
33641 33643 33645
band
+443 cm-1 bandA 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
PBSLaser
Photo-diode
Photo-diode
CW single-mode dye laser
Single mode UV laser beam
Doubling cavity