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Time-resolved extreme ultraviolet spectroscopy was used to investigate photodissociation within the iodobenzene C-band. The carbon-iodine bond of iodobenzene was photolyzed at 200 nm, and the ensuing dynamics were probed at 10.3 nm (120 eV) over a 4 ps range. Two product channels were observed and subsequently isolated by using a global fitting method. Their onset times and energetics were assigned to distinct electron transfer dynamics initiated following site-selective ionization of the iodine photoproducts, enabling the electronic states of the phenyl fragments to be identified using a classical over-the-barrier model for electron transfer. In combination with previous theoretical work, this allowed the corresponding neutral photochemistry to be assigned to (1) dissociation via the 7B 2 , 8A 2 , and 8B 1 states to give ground-state phenyl, Ph(X), and spin-orbit excited iodine and (2) dissociation through the 7A 1 and 8B 2 states to give excited-state phenyl, Ph(A), and ground-state iodine. The branching ratio was determined to be 87 ± 4% Ph(X) and 13 ± 4% Ph(A). Similarly, the corresponding amount of energy deposited into the internal phenyl modes in these channels was determined to be 44 ± 10 and 65 ± 21%, respectively, and upper bounds to the channel rise times were found to be 114 ± 6 and 310 ± 60 fs., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

The dissociative double ionization of CH3I and CH2I2 irradiated with extreme ultraviolet light at hv = 100 eV is investigated by multi-electron-ion coincidence spectroscopy using a magnetic bottle type electron spectrometer. The spin-orbit state-resolved Auger electron spectra for the I 4d core-hole states, (I 4d3/2)-1 and (I 4d5/2)-1, provide clear identifications of electronic states of CH3I2+ and CH2I22+. The dominant ion species produced after the double ionization correlate with the Auger electron energy, showing that different fragmentation pathways are open depending on the electronic states populated by the Auger decay. Theoretical calculations are performed to understand the fragmentation from the doubly charged states and the observed spin-orbit specificity in the Auger decay., (© 2024 Author(s). Published under an exclusive license by AIP Publishing.)

C-I bond extension and fission following ultraviolet (UV, 262 nm) photoexcitation of 2- and 3-iodothiophene is studied using ultrafast time-resolved extreme ultraviolet (XUV) ionization in conjunction with velocity map ion imaging. The photoexcited molecules and eventual I atom products are probed by site-selective ionization at the I 4d edge using intense XUV pulses, which induce multiple charges initially localized to the iodine atom. At C-I separations below the critical distance for charge transfer (CT), charge can redistribute around the molecule leading to Coulomb explosion and charged fragments with high kinetic energy. At greater C-I separations, beyond the critical distance, CT is no longer possible and the measured kinetic energies of the charged iodine atoms report on the neutral dissociation process. The time and momentum resolved measurements allow determination of the timescales and the respective product momentum and kinetic energy distributions for both isomers, which are interpreted in terms of rival 'direct' and 'indirect' dissociation pathways. The measurements are compared with a classical over the barrier model, which reveals that the onset of the indirect dissociation process is delayed by ∼1 ps relative to the direct process. The kinetics of the two processes show no discernible difference between the two parent isomers, but the branching between the direct and indirect dissociation channels and the respective product momentum distributions show isomer dependencies. The greater relative yield of indirect dissociation products from 262 nm photolysis of 3-iodothiophene ( cf. 2-iodothiophene) is attributed to the different partial cross-sections for (ring-centred) π∗ ← π and (C-I bond localized) σ∗ ← (n/π) excitation in the respective parent isomers.

Wave packet interferometry with vacuum ultraviolet light has been used to probe a complex region of the electronic spectrum of molecular nitrogen, N2. Wave packets of Rydberg and valence states were excited by using double pulses of vacuum ultraviolet (VUV), free-electron-laser (FEL) light. These wave packets were composed of contributions from multiple electronic states with a moderate principal quantum number (n ∼ 4-9) and a range of vibrational and rotational quantum numbers. The phase relationship of the two FEL pulses varied in time, but as demonstrated previously, a shot-by-shot analysis allows the spectra to be sorted according to the phase between the two pulses. The wave packets were probed by angle-resolved photoionization using an infrared pulse with a variable delay after the pair of excitation pulses. The photoelectron branching fractions and angular distributions display oscillations that depend on both the time delays and the relative phases of the VUV pulses. The combination of frequency, time delay, and phase selection provides significant control over the ionization process and ultimately improves the ability to analyze and assign complex molecular spectra., (© 2024 Author(s). Published under an exclusive license by AIP Publishing.)

Purpose: Preoperative pain is known as one of the most powerful risk factors for chronic postoperative inguinal pain (CPIP), while its pathogenesis has not been fully elucidated. The aim of the present study was to evaluate patients with preoperative pain from the pathological perspective and discuss the potential pathogenesis of CPIP in those patients., Methods: This was a single-institutional retrospective study. The study population was inguinal hernia patients with preoperative pain who underwent open anterior hernia repair for primary inguinal hernia with pragmatic ilioinguinal neurectomy during surgery between March 2021 and March 2023. The primary and secondary outcomes were proportion of collagen deposition and mucus accumulation within ilioinguinal nerve in those patients, respectively, which were evaluated histologically using Image J software., Results: Forty patients were evaluated. Median value of proportion of intraneural collagen deposition was 38.3% (27.7-95.9). These values were positively correlated with the duration of pain (r 2 =0.468, P<0.001). Median value of proportion of mucus accumulation in ilioinguinal nerve was 50.1% (0-82.0). These values had no correlation with any clinicopathological variables., Conclusions: In the present study population, all patients with preoperative pain had intraneural fibrosis within ilioinguinal nerve, and its degree had a positive correlation with the pain duration., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Laparoscopic total gastrectomy for gastric cancer is still a demanding operation because of technical difficulties, especially of intracorporeal esophago-jejunal anastomosis., Methods: We introduced a newly designed method of anvil placement of circular stapling devices (CS) for laparoscopic esophagojejunostomy (EJS). A small incision was made on the anterior wall of the stomach, from which the anvil was inserted into the stomach and proceeded to the thoracic esophagus. Then, the abdominal esophagus was transected by a linear stapler, and the anvil into the esophagus was drawn back to the esophageal stump by pulling out the cotton tape pre-attached to the anvil. Intracorporeal EJS by Roux-en-Y reconstruction was performed by CS inserted into the abdominal cavity from the umbilical wound., Results: A total of consecutive 200 gastric cancer patients underwent laparoscopic total gastrectomy using this method. There was no operative mortality. Anastomotic complications occurred in 12 cases (6.0%): 9 cases of stenosis (4.5%) and 3 cases of bleedings (1.5%). Anastomotic leakage was not observed. As for non-anastomotic complications, there occurred 2 pulmonary complications (1.0%), 3 pancreatic leakages (1.5%), and 8 bowel obstructions due to internal hernia (4.0%). With a median follow-up period of 47.1 months, 5-year overall survival for assessable patients (n = 193) was 60.3% (95% CI 52.6-67.2). The total rate of peritoneal recurrence was 9.8%., Conclusion: Our new method of anvil placement for laparoscopic EJS with CS is safe and feasible with favorable survival outcomes. It eliminates the need for suturing, and will promote the clinical application of laparoscopic total gastrectomy for gastric cancer., Clinical Trials: UMIN000046119., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Purpose: Anastomotic stenosis of esophagojejunostomy after total gastrectomy has a substantial impact on the postoperative quality of life of the patient. If conservative treatment doesn't work, surgical intervention should be considered. However, redoing esophagojejunostomy is an extremely demanding procedure. Especially in the case where the primary surgery was performed laparoscopically, it is an unmet problem to maintain minimal invasiveness in re-do surgery., Methods: We report 3 cases of re-do esophagojejunostomy laparoscopically performed for anastomotic stenosis after laparoscopic total gastrectomy in gastric cancer, in whom endoscopic balloon dilation did not work., Results: Each patient underwent a re-do esophagojejunostomy laparoscopically. The mean operation time was 293 min, and the mean blood loss was 56 ml. There was no anastomosis-related complication, and they were discharged from hospital on 11-16 postoperative days. At the time of discharge, oral food intake was 100% in each patient. One year after the operation, follow-up endoscopic exams showed no anastomotic stenosis., Conclusion: Re-do laparoscopic esophagojejunostomy for anastomotic stenosis after laparoscopic total gastrectomy was safely and successfully performed. It brings patients minimal invasiveness continuously from the initial surgery. Re-do laparoscopic esophagojejunostomy could be one of the options for anastomotic stenosis resistant to conservative treatment., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The effect of the incident UV pump wavelength on the subsequent excited state dynamics, electronic relaxation, and ultimate dissociation of formaldehyde is studied using first principles simulation and Coulomb explosion imaging (CEI) experiments. Transitions in a vibronic progression in the à ← X̃ absorption band are systematically prepared using a tunable UV source which generates pulses centered at 304, 314, 329, and 337 nm. We find, both via ab initio simulation and experimental results, that the rate of excited state decay and subsequent dissociation displays a prominent dependence on which vibronic transition in the absorption band is prepared by the pump. Our simulations predict that nonadiabatic transition rates and dissociation yields will increase by a factor of >100 as the pump wavelength is decreased from 337 to 304 nm. The experimental results and theoretical simulations are in broad agreement and both indicate that the dissociation rate plateaus rapidly after ≈2 ps following an ultrafast sub-ps rise.

A 67-year-old man with a low-grade fever was found to have a 25-mm diameter tumor of the left hepatic umbilical portion. The tumor was accompanied by occlusion of the left portal vein. Positron emission tomography using fluorodeoxyglucose showed that the tumor had abnormally high metabolic activity. Magnetic resonance imaging revealed the left hepatic duct segmental narrowing. There was a mild elevation in serum IgG4 (206 mg/dL). Intrahepatic cholangiocarcinoma was suspected. Instead of planned hepatectomy, the patient was forced to undergo emergency surgery for biliary panperitonitis caused by intrahepatic bile duct rupture. Intraoperative ultrasonography revealed a hypoechoic tumor-like thickened Glissonean sheath and needle biopsy was performed. Histologic examination confirmed fibrous tissue with IgG4-positive plasma cell infiltration without neoplastic proliferation. He was diagnosed with IgG4-related sclerosing cholangitis (IgG4-SC) presenting hepatic inflammatory pseudotumor. After his general condition improved, he underwent left hepatectomy. Macroscopic findings showed extreme fibrosis of the Glissonean sheath of the umbilical portion, and diffuse granular lesion aggregated in the left lateral segment. Microscopic examination confirmed chronic cholangitis and dense portal fibrosis in the umbilical portion and diffuse xanthogranulomatous inflammation. This is the first case report of spontaneous rupture of the intrahepatic bile duct in patient with IgG4-SC., (© 2021. Japanese Society of Gastroenterology.)

We have used the FERMI free-electron laser to perform time-resolved photoelectron imaging experiments on a complex group of resonances near 15.38 eV in the absorption spectrum of molecular nitrogen, N 2 , under jet-cooled conditions. The new data complement and extend the earlier work of Fushitani et al. [Opt. Express 27, 19702-19711 (2019)], who recorded time-resolved photoelectron spectra for this same group of resonances. Time-dependent oscillations are observed in both the photoelectron yields and the photoelectron angular distributions, providing insight into the interactions among the resonant intermediate states. In addition, for most states, we observe an exponential decay of the photoelectron yield that depends on the ionic final state. This observation can be rationalized by the different lifetimes for the intermediate states contributing to a particular ionization channel. Although there are nine resonances within the group, we show that by detecting individual photoelectron final states and their angular dependence, we can identify and differentiate quantum pathways within this complex system.

Since the discovery of roaming as an alternative molecular dissociation pathway in formaldehyde (H 2 CO), it has been indirectly observed in numerous molecules. The phenomenon describes a frustrated dissociation with fragments roaming at relatively large interatomic distances rather than following conventional transition-state dissociation; incipient radicals from the parent molecule self-react to form molecular products. Roaming has been identified spectroscopically through static product channel-resolved measurements, but not in real-time observations of the roaming fragment itself. Using time-resolved Coulomb explosion imaging (CEI), we directly imaged individual "roamers" on ultrafast time scales in the prototypical formaldehyde dissociation reaction. Using high-level first-principles simulations of all critical experimental steps, distinctive roaming signatures were identified. These were rendered observable by extracting rare stochastic events out of an overwhelming background using the highly sensitive CEI method., (Copyright © 2020, American Association for the Advancement of Science.)

The pulse duration of soft X-ray free-electron laser (FEL) pulses of SACLA BL1 (0.2-0.3 nC per bunch, 0.5-0.8 MeV) were characterized by photoelectron sideband measurements. The intensity of the He 1 s -1 photoelectron sidebands generated by a near-infrared femtosecond laser was measured as a function of the time delay between the two pulses using an arrival time monitor. From the width of the cross-correlation trace thus derived, the FEL pulse duration was evaluated to be 28 ± 5 fs full width at half-maximum in the photon energy range between 40 eV and 120 eV.

Ultrafast multiphoton ionization of Xe in strong extreme ultraviolet free-electron laser (FEL) fields (91 eV, 30 fs, 1.6×10^{12}  W/cm^{2}) has been investigated by multielectron-ion coincidence spectroscopy. The electron spectra recorded in coincidence with Xe^{4+} show characteristic features associated with two-photon absorption to the 4d^{-2} double core-hole (DCH) states and subsequent Auger decay. It is found that the pathway via the DCH states, which has eluded clear identification in previous studies, makes a large contribution to the multiple ionization, despite the long FEL pulse duration compared with the lifetime of the 4d core-hole states.

The ultrafast dynamics of molecular nitrogen (N 2 ) just below the ionization threshold has been investigated by time-resolved photoelectron spectroscopy using a single harmonic centered at hν = 15.38 eV. The evolution of the Rydberg wavepacket launched by the ultrashort EUV pulse is probed by a time-delayed femtosecond NIR laser pulse. The observed photoelectron spectra show two series of vibrational peaks to the ground X 2 Σg+ state and the first excited A 2 Πu state of N2+. Among these, two photoelectron peaks with the vibrational quantum numbers v X+ = 4 and v A+ = 1 exhibit clear anti-phase oscillation with a period of 300 fs, showing that two Rydberg states converging to the X 2 Σg+ and A 2 Πu ionic states interact with each other, thus causing periodic switching in the population of the ion core states.

Selective bond breaking of CO 2 in phase-locked ω-2ω two-color intense laser fields (λ = 800 nm and 400 nm, total field intensity I ∼ 10 14 W cm -2 ) has been investigated by coincidence momentum imaging. The CO + and O + fragment ions produced by two-body Coulomb explosion, CO 2 2+ → CO + + O + , exhibit asymmetric distributions along the laser polarization direction, showing that one of the two equivalent C-O bonds is selectively broken by the laser fields. At a field intensity higher than 2 × 10 14 W cm -2 , the largest fragment asymmetry is observed when the relative phase ϕ between the ω and 2ω laser fields is ∼0 and π. On the other hand, an increase of the asymmetry and a shift of the phase providing the largest asymmetry are observed at lower field intensities. The selective bond breaking and its dependence on the laser field intensity are discussed in terms of a mechanism involving deformation of the potential energy surfaces and electron recollision in intense laser fields.

We present applications of extreme ultraviolet (XUV) single-order laser harmonics to gas-phase ultrafast photoelectron spectroscopy. Ultrashort XUV pulses at 80 nm are obtained as the 5th order harmonics of the fundamental laser at 400 nm by using Xe or Kr as the nonlinear medium and separated from other harmonic orders by using an indium foil. The single-order laser harmonics is applied for real-time probing of vibrational wavepacket dynamics of I 2 molecules in the bound and dissociating low-lying electronic states and electronic-vibrational wavepacket dynamics of highly excited Rydberg N 2 molecules.

Tunneling-ionization imaging of photoexcitation of NO has been demonstrated by using few-cycle near-infrared intense laser pulses (8 fs, 800 nm, 1.1×10^{14}  W/cm^{2}). The ion image of N^{+} fragment ions produced by dissociative ionization of NO in the ground state, NO (X^{2}Π,2π)→NO^{+}+e^{-}→N^{+}+O+e^{-}, exhibits a characteristic momentum distribution peaked at 45° with respect to the laser polarization direction. On the other hand, a broad distribution centered at ∼0° appears when the A^{2}Σ^{+} (3sσ) excited state is prepared as the initial state by deep-UV photoexcitation. The observed angular distributions are in good agreement with the corresponding theoretical tunneling ionization yields, showing that the fragment anisotropy reflects changes of the highest-occupied molecular orbital by photoexcitation.

Nonlinear, three-photon double excitation of He in intense extreme ultraviolet free-electron laser fields (∼24.1  eV, ∼5  TW/cm2) is presented. Resonances to the doubly excited states converging to the He+ N=3 level are revealed by the shot-by-shot photoelectron spectroscopy and identified by theoretical calculations based on the time-dependent Schrödinger equation for the two-electron atom under a laser field. It is shown that the three-photon double excitation is enhanced by intermediate Rydberg states below the first ionization threshold, giving a greater contribution to the photoionization yields than the two-photon process by more than 1 order of magnitude.

A novel multi-electron-ion coincidence spectrometer developed on the basis of a 1.5 m-long magnetic-bottle electron spectrometer is presented. Electrons are guided by an inhomogeneous magnetic field to a detector at the end of the flight tube, while a set of optics is used to extract counterpart ions to the same detector, by a pulsed inhomogeneous electric field. This setup allows ion detection with high mass resolution, without impairing the high collection efficiency for electrons. The performance of the coincidence spectrometer was tested with double ionization of carbon disulfide, CS(2) → CS(2)(2+) + e(-) + e(-), in ultrashort intense laser fields (2.8 × 10(13) W/cm(2), 280 fs, 1030 nm) to clarify the electron correlation below the rescattering threshold.

The visualization of ultrafast isomerization of deuterated acetylene dication (C(2)D(2)(2+)) is demonstrated by time-resolved Coulomb explosion imaging with sub-10 fs intense laser pulses (9 fs, 0.13 PW cm(-2), 800 nm). The Coulomb explosion imaging monitoring the three-body explosion process, C(2)D(2)(3+)→ D(+) + C(+) + CD(+), as a function of the delay between the pump and probe pulses revealed that the migration of a deuterium atom proceeds in a recurrent manner; One of the deuterium atoms first shifts from one carbon site to the other in a short timescale (∼90 fs), and then migrates back to the original carbon site by 280 fs, in competition with the molecular dissociation. Correlated motion of the two deuterium atoms associated with the hydrogen migration and structural deformation to non-planar geometry are identified by the time-resolved four-body Coulomb explosion imaging, C(2)D(2)(4+)→ D(+) + C(+) + C(+) + D(+)., (© The Owner Societies 2011)

Generation of single-order laser harmonics in extreme ultraviolet (EUV) and the application to the time-resolved photoelectron spectroscopy of I(2) are demonstrated. The EUV pulses at 80 nm were generated from Kr as the 5th order harmonics of intense 400 nm laser pulses and then separated from other harmonic orders by a thin indium foil. The pump-probe photoelectron spectroscopy of I(2) in the B (3)Π(0(u)(+)) and B" (1)Π(1(u)) states excited by visible laser pulses at 490 nm showed a rapid increase in the yield of atomic iodine (~400 fs), reflecting the dissociation dynamics evolving simultaneously in the two excited states., (© 2011 Optical Society of America)

Photoelectron spectroscopy has been performed to study the multiphoton double ionization of Ar in an intense extreme ultraviolet laser field (hν ∼ 21  eV, ∼ 5  TW/cm²), by using a free electron laser (FEL). Three distinct peaks identified in the observed photoelectron spectra clearly show that the double ionization proceeds sequentially via the formation of Ar(+): Ar+hν→Ar (+) + e⁻ and Ar²(+) + 2hν→Ar(+) + e⁻. Shot-by-shot recording of the photoelectron spectra allows simultaneous monitoring of FEL spectrum and the multiphoton process for each FEL pulse, revealing that the two-photon ionization from Ar(+) is significantly enhanced by intermediate resonances in Ar(+).

Vibronic progressions are programmed into a pulse shaper which converts them via the inherent Fourier transformation into a train of femtosecond pulses in time domain for chromophore excitation. Double pulse results agree with phase-sensitive wave packet superposition from a Michelson interferometer which delivers coherence times with high reliability. Spectral resolution of 1 nm and a spacing of around 4 nm within the 20 nm envelope centered at 590 nm delivers a train of seven phase-controlled 40 fs subpulses separated by 250 fs. Combs adjusted to the zero phonon lines (ZPL) and phonon sidebands (PSB) of the B state vibronic progression are reproduced in the chromophore for a coherent subpulse accumulation. B state ZPL wave packet dynamics dominates in pump-probe spectra due to its coherence despite an overwhelming but incoherent A state contribution in absorption. PSB comb accumulation is also phase sensitive and demonstrates coherence within several 100 matrix degrees of freedom in the vicinity.

The fragmentation of deuterated benzene (C6D6) in ultrashort intense laser fields (9 fs, 1 x 10(15) W/cm2) is studied by the ion-coincidence momentum imaging technique. Five two-body and eight three-body Coulomb explosion pathways from the trication (C6D6(3+)), associated with the deprotonation and ring-opening reactions, are identified. It is found from the fragment momentum correlation that all the observed three-body explosion processes proceed sequentially via the two-body Coulomb explosion forming molecular dications, C(m)D(n)(2+), with (m,n) = (6,5), (5,5), (5,4), (4,4), (4,3), and (3,3), which further dissociate into pairs of monocations. The branching ratio of the fragmentation pathways estimated from the number of the observed coincidence events indicates that the fragmentation is nonstatistical.

The nuclear spin conversion of CH(4) and CD(4) isolated in solid parahydrogen was investigated by high resolution Fourier transform infrared spectroscopy. From the analysis of the temporal changes of rovibrational absorption spectra, the nuclear spin conversion rates associated with the rotational relaxation from the J=1 state to the J=0 state for both species were determined at temperatures between 1 and 6 K. The conversion rate of CD(4) was found to be 2-100 times faster than that of CH(4) in this temperature range. The faster conversion in CD(4) is attributed to the quadrupole interaction of D atoms in CD(4), while the conversion in CH(4) takes place mainly through the nuclear spin-nuclear spin interaction. The conversion rates depend on crystal temperature strongly above 3.5 K for CH(4) and above 2 K for CD(4), while the rates were almost constant below these temperatures. The temperature dependence indicates that the one-phonon process is dominant at low temperatures, while two-phonon processes become important at higher temperatures as a cause of the nuclear spin conversion.

The isomerization of acetylene via hydrogen migration in intense laser fields (8 x 10(14) W/cm2) has been investigated by coincidence momentum imaging of the three-body Coulomb explosion process, C2H2 (3+)-->H+ + C+ + CH+. When ultrashort (9 fs) laser pulses are used, the angle between the momenta of C+ and H+ fragments exhibits a sharp distribution peaked at a small angle ( approximately 20 degrees ), showing that the hydrogen atom remains near the original carbon site in the acetylene configuration. On the other hand, a significantly broad distribution extending to larger momentum angles ( approximately 120 degrees ) is observed when the pulse duration is increased to 35 fs, indicating that the ultrafast isomerization to vinylidene is induced in the longer laser pulse.

We demonstrate the visualization of ultrafast hydrogen migration in deuterated acetylene dication (C2D2{2+}) by employing the pump-probe Coulomb explosion imaging with sub-10-fs intense laser pulses (9 fs, 0.13 PW/cm{2}, 800 nm). It is shown, from the temporal evolution of the momenta of the fragment ions produced by the three-body explosion, C2D2{3+}-->D{+} + C{+} + CD{+}, that the migration proceeds in a recurrent manner: the deuterium atom first shifts from one carbon site to the other in a short time scale (approximately 90 fs) and then migrates back to the original carbon site by 280 fs, in competition with the molecular dissociation.

Photochemical reactions of molecules in solid orthodeuterium (o-D2) have been studied by high-resolution infrared spectroscopy and compared with previous results obtained in solid parahydrogen (p-H2). Ultraviolet photolysis of CD3I molecules in solid o-D2 yielded CD3 radicals and iodine atoms efficiently, which indicates a small cage effect in solid o-D2, as in the case of solid p-H2. The Fourier transform infrared spectrum of the nu3 vibrational band of CD3 showed a rotational structure with additional splitting due to crystal field interactions. The magnetic dipole transition (2P1/2<--2P3/2) of the I atom isolated in solid o-D2 was observed together with a strong rotational satellite of deuterium molecules through the electron-roton coupling in solid hydrogen. The tunneling reaction between CD3 and D2 was not observed in a time scale of a few days, which gives the upper limit of the tunneling reaction rate of 10(-8) s(-1) at 4.2 K.

We perform time resolved pump-probe spectroscopy on small halogen molecules ClF, Cl2, Br2, and I2 embedded in rare gas solids (RGS). We find that dissociation, angular depolarization, and the decoherence of the molecule is strongly influenced by the cage structure. The well ordered crystalline environment facilitates the modelling of the experimental angular distribution of the molecular axis after the collision with the rare gas cage. The observation of many subsequent vibrational wave packet oscillations allows the construction of anharmonic potentials and indicate a long vibrational coherence time. We control the vibrational wave packet revivals, thereby gaining information about the vibrational decoherence. The coherence times are remarkable larger when compared to the liquid or high pressure gas phase. This fact is attributed to the highly symmetric molecular environment of the RGS. The decoherence and energy relaxation data agree well with a perturbative model for moderate vibrational excitation and follow a classical model in the strong excitation limit. Furthermore, a wave packet interferometry scheme is applied to deduce electronic coherence times. The positions of those cage atoms, excited by the molecular electronic transitions are modulated by long living coherent phonons of the RGS, which we can probe via the molecular charge transfer states.

Femtosecond dynamics of molecular vibrations as well as cage motions in the B<--X transition of Cl2 in solid Ar have been investigated. We observed molecular vibrational wave-packet motion in experimental pump-probe spectra and an additional oscillation with a 500 fs period which is assigned to the zone-boundary phonon of the Ar crystal. The cage motion is impulsively driven by the B<--X transition due to the expansion of the electronic cloud of the chromophore. To clarify the underlying mechanism, we performed simulations based on the diatomics-in-molecules method which takes into account the different shapes of the Cl2 electronic wave function in the B and X states as well as the anisotropic interaction with the matrix. The simulation results show that Ar atom motion in the (100) plane is initiated by the electronic transition and that only those Ar atoms oscillate coherently with an approximately 500 fs period which are essentially decoupled from the molecular vibration. Their phase and time evolution are in good agreement with the experimentally observed oscillation, supporting the assignment as a displacive excitation of coherent phonons.

Electronic and vibrational coherences of Cl2 embedded in solid Ar are investigated by exciting to the B state with a phase-locked pulse pair from an unbalanced Michelson interferometer, where the chirp difference matches the B state anharmonicity. Recording the A' --> X fluorescence after relaxation is compared to probing to charge transfer states by a third pulse. The three-pulse experiment delivers more details on the decoherence processes. The signal modulation due to phase tuning up to the third vibrational round-trip time indicates that the electronic coherence in the B <-- X transition is preserved for more than 660 fs in the solid Ar environment where many body electronic interactions take place. Vibrational coherence lasts longer than 3 ps according to the observed half revival of the wavepacket. Control of the coupling between wavepacket motion and lattice oscillation is demonstrated by tuning the relative phase between the phase-locked pulses, preparing wavepackets predominantly composed of either zero-phonon lines or phonon side bands.

Tunneling chemical reactions between deuterated methyl radicals and the hydrogen molecule in a parahydrogen crystal have been studied by Fourier transform infrared spectroscopy. The tunneling rates of the reactions R + H2 --> RH + H (R = CD3,CD2H,CDH2) in the vibrational ground state were determined directly from the temporal change in the intensity of the rovibrational absorption bands of the reactants and products in each reaction in solid parahydrogen observed at 5 K. The tunneling rate of each reaction was found to differ definitely depending upon the degree of deuteration in the methyl radicals. The tunneling rates were determined to be 3.3 x 10(-6) s(-1), 2.0 x 10(-6) s(-1), and 1.0 x 10(-6) s(-1) for the systems of CD3, CD2H, and CDH2, respectively. Conversely, the tunneling reaction between a CH3 radical and the hydrogen molecule did not proceed within a week's time. The upper limit of the tunneling rate of the reaction of the CH3 radical was estimated to be 8 x 10(-8) s(-1)., ((c) 2004 American Institute of Physics.)

We report the preliminary results of our experiments with stimulated Raman scattering in para-hydrogen crystal aimed at developing a continuously tunable laboratory laser source of mid-infrared radiation. With laser pulses at 532 nm, a conversion efficiency for the first Stokes beam of as much as 20% in the forward direction was observed through a single-pass, 5-cm-long crystal. Generation of mid-infrared pulses at 4.5 microm was achieved by use of the output of a near-infrared pulsed laser (1.6 microm, 3 ns), and an absorption spectrum of gaseous CD4 molecules was successfully recorded. These results suggest use of the solid para-hydrogen Raman shifter as a promising light source for mid-infrared spectroscopy.

Abscisic acid (ABA) in the stem of akamatsu (Pinus densiflora) was identified and quantified by gas chromatography-mass spectrometry-selected ion monitoring using hexadeuterated ABA as an internal standard. tert-Butyldimethylsilyl ester was used as a derivative of ABA. This derivative had high sensitivity and selectivity for ABA determination. ABA concentrations in cambial region scrapings were independent of the cessation of cambial activity.