JOPSS - Search Results

Journal Articles

High-pressure-high-temperature study of benzene; Refined crystal structure and new phase diagram up to 8 GPa and 923 K

Chanyshev, A. D.*; Litasov, K. D.*; Rashchenko, S.*; Sano, Asami; Kagi, Hiroyuki*; Hattori, Takanori; Shatskiy, A. F.*; Dymshits, A. M.*; Sharygin, I. S.*; Higo, Yuji*

Crystal Growth & Design, 18(5), p.3016 - 3026, 2018/05

https://doi.org/10.1021/acs.cgd.8b00125

Times Cited Count：21 Percentile：84.44(Chemistry, Multidisciplinary)

The high-temperature structural properties of solid benzene were studied at 1.5-8.2 GPa up to melting or decomposition using multi-anvil apparatus and in situ neutron and X-ray diffraction. The crystal structure of deuterated benzene phase II (P2 $_{1}$ /c unit cell) was refined at 3.6-8.2 GPa and 473-873 K. Our data show a minor temperature effect on the change in the unit cell parameters of deuterated benzene at 7.8-8.2 GPa. At 3.6-4.0 GPa, we observed the deviation of deuterium atoms from the benzene ring plane and minor zigzag deformation of the benzene ring, enhancing with the temperature increase caused by the displacement of benzene molecules and decrease of van der Waals bond length between the -conjuncted carbon skeleton and the deuterium atom of adjacent molecule. Deformation of benzene molecule at 723-773 K and 3.9-4.0 GPa could be related to the benzene oligomerization at the same conditions. In the pressure range of 1.5-8.2 GPa, benzene decomposition was defined between 773-923 K. Melting was identified at 2.2 GPa and 573 K. Quenched products analyzed by Raman spectroscopy consist of carbonaceous material. The defined benzene phase diagram appears to be consistent with those of naphthalene, pyrene, and coronene at 1.5-8 GPa.

Journal Articles

Mechanism of state-specific enhancement in photon-stimulated desorption as studied using a polarization-dependent technique

Sekiguchi, Tetsuhiro; Baba, Yuji; Shimoyama, Iwao; Wu, G.*; Kitajima, Yoshinori*

Surface Science, 593(1-3), p.310 - 317, 2005/11

https://doi.org/10.1016/j.susc.2005.06.076

Times Cited Count：2 Percentile：11.16(Chemistry, Physical)

Using a newly developed rotatable time-of-flight mass spectrometer(R-TOF-MS) and polarized synchrotron radiation, orientation effect on fragmentation and desorption pathways occurring at the top-most layers of molecular solids have been investigated. Reported will be polarization-angle dependencies of TOF mass spectra, high-resolution electron- and ion-NEXAFS in condensed chlorobenzene.

Journal Articles

Element- and orientation-selective photo-fragmentation using polarized synchrotron radiation

Sekiguchi, Tetsuhiro; Ikeura-Sekiguchi, Hiromi*; Baba, Yuji; Shimoyama, Iwao; Nath, K. G.

Photon Factory Activity Report 2002, Part B, P. 80, 2003/11

http://pfwww.kek.jp/acr2002pdf/part_b/pf02b080.pdf

no abstracts in English

Journal Articles

Orientation effect on phot-fragmentation and ion-desorption from the topmost layers of molecular solids

Sekiguchi, Tetsuhiro; Ikeura, Hiromi*; Baba, Yuji

Surface Science, 532-535(1-3), p.1079 - 1084, 2003/06

Using a newly developed rotatable time-of-flight mass spectrometer(R-TOF-MS) and polarized synchrotron radiation, we have investigated orientation effect on fragmentation and desorption pathways occurring at the top-most layers of molecular solids. Reported will be polarization-angle dependencies of TOF mass spectra, high-resolution electron- and ion-NEXAFS in condensed formic acid, formamide and benzene. For condensed formamide(HCOND $_{2}$ ), marked orientation effect was observed for the enhanced H $^{+}$ -yields following C1s * $_{C-H}$ resonance. Direct photodissociation and charge-neutralization play an important role in the effect. For some fragment species, however, the bond scission showed no polarization dependence when dissociation sites were far from core-excited atoms. This is the case for N-D scission and D $^{+}$ -desorption following C1s excitation, suggesting that indirect process governs, where secondary electrons would induce the fragmentation.