Sub-Doppler Zeeman spectroscopy of pyrazine: S1 1B3u–S 1A
 g 0 band

Yamamoto, Norimasa; Ebi, Tsuyoshi; Baba, Masaaki

doi:10.1063/1.472419

Cited by 5 publications

(6 citation statements)

References 36 publications

(51 reference statements)

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“…We conclude that the triplet mixing is very weak and that the ISC process is very slow as in naphthalene. 33,34 These results contrast with those of glyoxal 35 and pyrazine 36 which show remarkable Zeeman shift and splitting even in a weak magnetic field. El-Sayed's rule also indicates that the S 1 ͑ 1 n ‫ء‬ ͒ state is strongly mixed with the 3 ‫ء‬ state.…”

Section: Discussioncontrasting

confidence: 81%

Rotationally resolved ultrahigh-resolution laser spectroscopy of the S2 A11←S A11 transition of azulene

Semba

Yoshida

Kasahara

et al. 2009

The Journal of Chemical Physics

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We have observed rotationally resolved ultrahigh-resolution fluorescence excitation spectra of the 0(0)(0) (a-type) and 0(0)(0)+467 cm(-1) (b-type) bands of the S(2) (1)A(1)<--S(0) (1)A(1) transition of jet-cooled azulene. The observed linewidth is 0.0017 cm(-1), which corresponds to the lifetime of 3.1 ns in the S(2) state. Zeeman splitting of rotational lines is very small so that intersystem crossing to the triplet state is considered to be very slow. Inertial defect is very small and the molecule is considered to be planar in the S(0) and S(2) states (C(2v) symmetry). Rotational constants of the S(2) state are almost identical to those of the S(0) state, indicating that geometrical structure is similar in both electronic states. In this case, internal conversion (IC) by vibronic coupling is thought to be inactive. Therefore, the main radiationless transition process in the S(2) (1)A(1) state of azulene was identified to be IC to the S(1) (1)B(2) state. However, this S(2)-->S(1) IC is still slower than that of conventional polycyclic aromatic hydrocarbons. We consider it to be due to the shallower potential energy curve in the S(1) (1)B(2) state, which is also responsible for the extraordinarily fast S(1)-->S(0) IC in the isolated azulene molecule.

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Section: Discussioncontrasting

confidence: 81%

Rotationally resolved ultrahigh-resolution laser spectroscopy of the S2 A11←S A11 transition of azulene

Semba

Yoshida

Kasahara

et al. 2009

The Journal of Chemical Physics

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“…In contrast, large Zeeman broadening and shifts of the rotational lines by the external magnetic field were observed in pyrazine 23 and glyoxal, 24 in which the S 1 ( 1 nπ ) and T 2 ( 3 ππ ) states are close in energy. In perylene, however, it has been shown that the singlet-triplet interaction is very weak and that the ISC is very slow at the S 1 zero-vibrational level.…”

Section: Resultsmentioning

confidence: 86%

Mode-selective internal conversion of perylene

et al. 2011

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We observed fluorescence excitation spectra and dispersed fluorescence spectra for single vibronic level excitation of jet-cooled perylene-h 12 and perylene-d 12 , and carefully examined the vibrational structure of the S 0 1 A g and S 1 1 B 2u states. We performed vibronic assignments on the basis of the results of ab initio calculation, and found that the vibrational energies in the S 1 state are very similar to those in the S 0 state, indicating that the potential energy curves are not changed much upon electronic excitation. We conclude that the small structural change is the main cause of its slow radiationless transition and high fluorescence quantum yield at the zero-vibrational level in the S 1 state. It has been already reported that the lifetime of perylene is remarkably short at specific vibrational levels in the S 1 state. Here, we show that the mode-selective nonradiative process is internal conversion (IC) to the S 1 state, and the ν 16 (a g) 1 in-plane ring deforming vibration is the promoting (doorway) mode in the S 1 state which enhances vibronic coupling with the high-vibrational level (b 2u) of the S 0 state.

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“…We found no energy shift occurring as a result of local perturbation; accordingly, the mixing with the triplet state is considered to be small. We have already identified many level shifts and large Zeeman broadening in the S 1 (np * ) states of glyoxal [22] and pyrazine [23], in which the singlet-triplet coupling through spin-orbit interaction is strong. We have now observed the ultrahigh-resolution spectrum of perylene in the external magnetic field of 1 Tesla.…”

Section: Resultsmentioning

confidence: 95%

Ultrahigh-resolution laser spectroscopy of the S1 1B2← S0 1A transition of perylene

Kowaka¹,

Suganuma²,

Ashizawa³

et al. 2010

Journal of Molecular Spectroscopy

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a b s t r a c tA rotationally resolved ultrahigh-resolution fluorescence excitation spectrum of the S 1 S 0 transition of perylene has been observed using a collimated supersonic jet technique in conjunction with a single-mode UV laser. We assigned 1568 rotational lines of the 0 0 0 band, and accurately determined the rotational constants. The obtained value of inertial defect was positive, accordingly, the perylene molecule is considered to be planar with D 2h symmetry. We determined the geometrical structure in the S 0 state by ab initio theoretical calculation at the RHF/6-311+G(d,p) level, which yielded rotational constant values approximately identical to those obtained experimentally. Zeeman broadening of each rotational line with the external magnetic field was negligibly small, and the mixing with the triplet state was shown to be very small. This evidence indicates that intersystem crossing (ISC) in the S 1 1 B 2u state is very slow. The rate of internal conversion (IC) is also inferred to be small because the fluorescence quantum yield is high. The rotational constants of the S 1 1 B 2u state were very similar to those of the S 0 1 A g state. The slow internal conversion (IC) at the S 1 zero-vibrational level is attributed to a small structural change upon electronic transition.

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Sub-Doppler Zeeman spectroscopy of pyrazine: S1 1B3u–S 1A g 0 band

Cited by 5 publications

References 36 publications

Rotationally resolved ultrahigh-resolution laser spectroscopy of the S2 A11←S A11 transition of azulene

Rotationally resolved ultrahigh-resolution laser spectroscopy of the S2 A11←S A11 transition of azulene

Mode-selective internal conversion of perylene

Ultrahigh-resolution laser spectroscopy of the S1 1B2← S0 1A transition of perylene

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