Oxygen molecules doped in a low temperature N2 crystal were irradiated at 240-260 nm. Two emission band systems were observed, one from the v&#8242; &#61; 0 level of A&#8242; 3<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mtext>&#x0394;</mml:mtext><mml:mtext>u</mml:mtext></mml:msub></mml:mrow></mml:math> state to X3<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>&#x03A3;</mml:mi><mml:mtext>g</mml:mtext></mml:msub></mml:mrow></mml:math>-. state and the other, from the v&#8242; &#61; 0 level of c1<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>&#x03A3;</mml:mi><mml:mtext>u</mml:mtext></mml:msub></mml:mrow></mml:math>-. state to at a1<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mtext>&#x0394;</mml:mtext><mml:mtext>g</mml:mtext></mml:msub></mml:mrow></mml:math> state, independent on the excitation wave length. The latter emission grew together with the decay of the former emission at around the same rate after the pulsed laser excitation, which implies that the vibrational levels of c state lying below the v&#8242; &#61; 0 level of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mtext>&#x03A9;</mml:mtext></mml:math> &#61; 3 of A&#8242; state are populated from the v&#8242; &#61; level of A&#8242; state, though some additional mechanism for populating the c state may exist. The rate was found to become larger with the increase of the crystal temperature. It was also found that the excitation spectrum obtained by monitoring the A&#8242;&#8211;X emission was the same as that obtained by the c&#8211;a emission. The progress of vibrational relaxation, coupling with the intersystem crossing between the Herzberg states, will be discussed.

Hideo  Kajihara

Tomoyuki  Okamura

Fumio  Okada

Seiichiro  Koda

Emission and Relaxation of Electronically Excited O2 Doped in a Low Temperature N2 Crystal

The geometric structures of 7-azaindole (7-AzI) and its dimer were investigated by laser-induced fluorescence (LIF). The rotationally resolved LIF spectrum (resolution: &#8764;0.00003 cm-1 of 7-AzI monomer shows that (i) rotational constants are A&#8242;&#8242; 0.13082(5), B&#8242;&#8242; &#61; 0.05677(2), C&#8242;&#8242; &#61; 0.03970(1), A&#8242; &#61; 0.12468(5), B&#8242; &#61; 0.056752(2), and C&#8242; &#61; 0.03911(1), and (ii) the transition dipole moment direction is tilted at an angle of &#177; 21(5) degrees with respect to a axis. The LIF spectrum (resolution: &#8764;0.06 cm-1) of the nonreactive 7-AzI dimer suggests there are three possibilities for the geometric structure, having &#8220;single bonded&#8221;, &#8220;T-shaped&#8221;, and &#8220;non-planar&#8221; structures.The ionization energy of 7-AzI was determined to be 8.1171(5) eV by using pulsed-field ionization photoelectron spectroscopy (PFI-PES). Several vibronic bands of 7-AzI cation were observed and compared with those of neutral 7-AzI in the S0 and S1 states. The electron binding energies of 7-AzI cluster anions (2 &#8804; n &#8804; 5) were determined by photoelectron spectroscopy.

A.  Nakajima

F.  Ono

Y.  Kihara

A.  Ogawa

K.  Matsubara

K.  Ishikawa

M.  Baba

k.  kaya

Spectroscopic Study of Hydrogen Bonded7-Azaindole Clusters

C. B. Moore

Energy Transfer With Soji Tsuchiya

The optical spectra of neutral atoms are studied in superfluid helium (HeII). Neutral atoms are dispersedinto HeII by laser ablation of solid samples immersed in HeII. Absorption and emission spectra of dispersed atoms are studied with pulsed dye lasers. Ytterbium is found to be a typical bubble atom which resides in a bubble-like cavity formed by a strong repulsive force against the surrounding He atoms. Resonance quenching of LIF by accidental overlap of the resonant induced emission and broad absorption lines is observed.

Qin  Hui

John L. Persson

Jaap H. M. Beijersbergen

Michio  Takami

Laser Spectroscopy of Neutral Atoms in Superfluid Helium: New Environment For Spectroscopy and Chemistry

R. W. Field

A Trans-Pacific Collaboration: Dynamical Experiments and Experiences

The photodissociation of mass-selected benzene cluster ions, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:msub><mml:mtext>C</mml:mtext><mml:mtext>6</mml:mtext></mml:msub><mml:msub><mml:mtext>H</mml:mtext><mml:mtext>6</mml:mtext></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mi>n</mml:mi><mml:mo>+</mml:mo></mml:msubsup></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mi>n</mml:mi><mml:mo>=</mml:mo><mml:mn>2</mml:mn><mml:mo>&#x2212;</mml:mo><mml:mn>8</mml:mn></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow></mml:math>, is studied to elucidate the dynamics of dissociation and the mechanism of fragmentation. For <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:msub><mml:mtext>C</mml:mtext><mml:mtext>6</mml:mtext></mml:msub><mml:msub><mml:mtext>H</mml:mtext><mml:mtext>6</mml:mtext></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mn>2</mml:mn><mml:mo>+</mml:mo></mml:msubsup></mml:mrow></mml:math>, the average translational energy and the angular distributions of the photofragments are measured as a function of photon energy (hv). The photoexcitation to an upper bound state with hv &#61; 2.81 eV results in statistical energy disposal. Regardless of the excitation to a dissociative state with hv &#61; 1.17-1.62 eV, only a small fraction (at most 10&#37;) of the available energy is partitioned into the translation. For <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:msub><mml:mtext>C</mml:mtext><mml:mtext>6</mml:mtext></mml:msub><mml:msub><mml:mtext>H</mml:mtext><mml:mtext>6</mml:mtext></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mi>n</mml:mi><mml:mo>+</mml:mo></mml:msubsup></mml:mrow></mml:math> with n &#61; 5-8, the average number of neutral molecules ejected following photoexcitation increases linearly with increasing hv until <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:msub><mml:mtext>C</mml:mtext><mml:mtext>6</mml:mtext></mml:msub><mml:msub><mml:mtext>H</mml:mtext><mml:mtext>6</mml:mtext></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mn>2</mml:mn><mml:mo>+</mml:mo></mml:msubsup></mml:mrow></mml:math> is reached as the product. The result suggests that the photofragmentation proceeds via the sequential evaporation of neutral monomers rather than the direct ejection of a neutral cluster.

Kazuhiko  Ohashi

Yasuhiro  Nakai

Nobuyuki   Nishi

Photodissociation Mechanisms of Benzene Cluster Ions on the Excitation With hv &#61; 0.5-3.0 eV

The overall rate constant for the reaction NH(<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mtext>a</mml:mtext><mml:mtext>1</mml:mtext></mml:msup><mml:mtext>&#x0394;</mml:mtext></mml:mrow></mml:math>) &#43; HN3 has been determined by the laser photolysis of hydrogen azide (HN3) at 266 nm and 193nm. The visible emission from vibronically excited NH2(<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mtext>A</mml:mtext><mml:mo>&#x02DC;</mml:mo></mml:mover></mml:math>2A1) was dispersed and its time-dependent profiles were measured at several wavelengths. The rate constants are dependent not only on the photolysis wavelengths but also on the vibrational levels of the NH2(<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mtext>A</mml:mtext><mml:mo>&#x02DC;</mml:mo></mml:mover></mml:math>2A1) produced in the reaction. The intermolecular potential between NH(<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mtext>a</mml:mtext><mml:mtext>1</mml:mtext></mml:msup><mml:mtext>&#x0394;</mml:mtext></mml:mrow></mml:math>) and HN3 was determined to be the form V(R) &#61; &#8211;C/Rs (2 &#60; s &#60; 4, C: constant) from the analysis with a long-range potential approximation. The interaction between NH(<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mtext>a</mml:mtext><mml:mtext>1</mml:mtext></mml:msup><mml:mtext>&#x0394;</mml:mtext></mml:mrow></mml:math>) and HN3 is mainly governed by the dipoledipole interaction in the initial stage of the reaction.

Akihiro  Watanabe

Katsuyoshi  Yamasaki

Ikuo  Tokue

Collision Energy Dependence of the Overall Rate Constant for the Reaction NH(<svg style="vertical-align:-0.16379pt" height="16.049999" version="1.1" viewBox="0 0 24.737499 16.049999" width="24.737499" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,15.775)"><path id="x61" d="M433 39l-85 -51q-27 0 -47 20q-16 16 -24 44q-5 -3 -24 -16.5t-27 -18.5t-23 -13.5t-25 -12t-19 -3.5q-52 0 -86 36.5t-34 85.5q0 71 81 99q128 43 155 65v17q0 54 -23 83.5t-62 29.5q-28 0 -45 -19t-29 -66q-7 -23 -29 -23q-15 0 -29 13t-14 30t31 40q25 19 68.5 40.5&#xA;t81.5 29.5q49 0 82 -27q45 -39 45 -123v-185q0 -60 35 -60q18 0 36 11zM275 84v156q-12 -6 -49 -23t-41 -19q-31 -14 -46 -31t-15 -43q0 -35 22.5 -55.5t48.5 -20.5q19 0 42 10.5t38 25.5z" /></g><g transform="matrix(.012,-0,0,-.012,7.525,7.613)"><path id="x31" d="M384 0h-275v27q67 5 81.5 18.5t14.5 68.5v385q0 38 -7.5 47.5t-40.5 10.5l-48 2v24q85 15 178 52v-521q0 -55 14.5 -68.5t82.5 -18.5v-27z" /></g><g transform="matrix(.017,-0,0,-.017,13.863,15.775)"><path id="x1D6E5" d="M613 23l-5 -23h-591l5 23l409 637l29 7zM517 51l-111 504l-307 -504h418z" /></g></svg>) &#x2B; HN3

About this journal

Journal profile

Meet the editorial board

Editor spotlight

Submit your proposal

Do you think there is an emerging area of research that really needs to be highlighted? Or an existing research area that has been overlooked or would benefit from deeper investigation? Raise the profile of a research area by leading a Special Issue.

Special Issues

title

https://images.hindawi.com/journals/lc/lc.banner.jpg

twitter:card

twitter:site

twitter:title

twitter:url

twitter:image

Laser Chemistry | Hindawi

Laser Chemistry

This Issue is now open for submissions.
Papers are published upon acceptance, regardless of the Special Issue publication date.

Call for papers

Koji Kaya