The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
David Lee Phillips - One of the best experts on this subject based on the ideXlab platform.
-
Resonance Raman intensity analysis of the excited state proton transfer dynamics of 2-nitrophenol in the charge-transfer band absorption.
The Journal of chemical physics, 2006Co-Authors: Ya-qiong Wang, Huigang Wang, Shu-qiang Zhang, Ke-mei Pei, Xuming Zheng, David Lee PhillipsAbstract:Resonance Raman spectra were obtained for 2-nitrophenol in cyclohexane solution with excitation wavelengths in resonance with the charge-transfer (CT) proton transfer band absorption. These spectra indicate that the Franck-Condon region photodissociation dynamics have multidimensional character with motion along more than 15 normal modes: the nominal CCH bend+CC stretch nu(12) (1326 cm(-1)), the nominal CCC bend nu(23) (564 cm(-1)), the nominal CO stretch+NO stretch+CC stretch nu(14) (1250 cm(-1)), the nominal CCH bend+CC stretch+COH bend nu(15) (1190 cm(-1)); the nominal CCH bend+CC stretch nu(17) (1134 cm(-1)), the nominal CCC bend+CC stretch nu(22) (669 cm(-1)), the nominal CCN bend nu(27) (290 cm(-1)), the nominal NO(2) bend+CC stretch nu(21) (820 cm(-1)), the nominal CCO bend+CNO bend nu(25) (428 cm(-1)), the nominal CC stretch nu(7) (1590 cm(-1)), the nominal NO stretch nu(8) (1538 cm(-1)), the nominal CCC bend+NO(2) bend nu(20) (870 cm(-1)), the nominal CC stretch nu(6) (1617 cm(-1)), the nominal COH bend+CC stretch nu(11) (1382 cm(-1)), nominal CCH bend+CC stretch nu(9) (1472 cm(-1)). A preliminary resonance Raman intensity analysis was done and the results for 2-nitrophenol were compared to previously reported results for nitrobenzene, p-nitroaniline, and 2-hydroxyacetophenone. The authors briefly discuss the differences and similarities in the CT-band absorption excitation of 2-nitrophenol relative to those of nitrobenzene, p-nitroaniline, and 2-hydroxyacetophenone.
-
resonance raman intensity analysis of the excited state proton transfer dynamics of 2 nitrophenol in the charge transfer band absorption
Journal of Chemical Physics, 2006Co-Authors: Ya-qiong Wang, Huigang Wang, Shu-qiang Zhang, Xuming Zheng, David Lee PhillipsAbstract:Resonance Raman spectra were obtained for 2-nitrophenol in cyclohexane solution with excitation wavelengths in resonance with the charge-transfer (CT) proton transfer band absorption. These spectra indicate that the Franck-Condon region photodissociation dynamics have multidimensional character with motion along more than 15 normal modes: the nominal CCH bend+CC stretch ν12 (1326cm−1), the nominal CCC bend ν23 (564cm−1), the nominal CO stretch+NO stretch+CC stretch ν14 (1250cm−1), the nominal CCH bend+CC stretch+COH bend ν15 (1190cm−1); the nominal CCH bend+CC stretch ν17 (1134cm−1), the nominal CCC bend+CC stretch ν22 (669cm−1), the nominal CCN bend ν27 (290cm−1), the nominal NO2 bend+CC stretch ν21 (820cm−1), the nominal CCO bend+CNO bend ν25 (428cm−1), the nominal CC stretch ν7 (1590cm−1), the nominal NO stretch ν8 (1538cm−1), the nominal CCC bend+NO2 bend ν20 (870cm−1), the nominal CC stretch ν6 (1617cm−1), the nominal COH bend+CC stretch ν11 (1382cm−1), nominal CCH bend+CC stretch ν9 (1472cm−1). A pr...
-
a band resonance raman spectra of 1 2 diiodoethane in cyclohexane solution substituent effects on the 1 halo 2 iodoethane short time photodissociation dynamics
Chemical Physics Letters, 1998Co-Authors: Xuming Zheng, Yung Fong Cheng, David Lee PhillipsAbstract:Abstract Resonance Raman spectra of 1,2-diiodoethane in cyclohexane solution have been obtained in the A-band absorption. A resonance Raman intensity analysis was done to examine the short-time photodissociation dynamics of 1,2-diiodoethane. Significant bond length and bond angle changes were found for both C–I bonds and the C–C bond as well as the CCI and HCH bond angles. Comparison of the Franck–Condon region dynamics of 1,2-diiodoethane with diiodomethane suggests that the degree of coupling of the two C–I chromophores depends on both the relative geometry of the C–I bonds and their relative separation.
Miroslaw Salamonczyk - One of the best experts on this subject based on the ideXlab platform.
-
structure of nanoscale pitch helical phases blue phase and twist bend nematic phase resolved by resonant soft x ray scattering
Soft Matter, 2017Co-Authors: Miroslaw Salamonczyk, Natasa Vaupotic, Damian Pociecha, Cheng Wang, Ewa GoreckaAbstract:Periodic structures of phases with orientational order of molecules but homogenous electron density distribution: a short pitch cholesteric phase, blue phase and twist-bend nematic phase, were probed by resonant soft X-ray scattering (RSoXS) at the carbon K-edge. The theoretical model shows that in the case of a simple heliconical nematic structure, two resonant signals corresponding to the full and half pitch band should be present, while only the full pitch band is observed experimentally. This suggests that the twist-bend nematic phase has a complex structure with a double-helix built of two interlocked, shifted helices. We confirm that the helical pitch in the twist-bend nematic phase is in a 10 nm range for both the chiral and achiral materials. We also show that the symmetry of the blue phase can be unambiguously determined through a resonant enhancement of the X-ray diffraction signals, by including polarization effects, which are found to be an important indicator in phase structure determination.
-
structure of nanoscale pitch helical phases blue phase and twist bend nematic phase resolved by resonant soft x ray scattering
arXiv: Soft Condensed Matter, 2017Co-Authors: Miroslaw Salamonczyk, Natasa Vaupotic, Damian Pociecha, Cheng Wang, Ewa GoreckaAbstract:Periodic structures of phases with orientational order of molecules, but homogenous electron density distribution: a short pitch cholesteric, blue phase and twist-bend nematic phase, were probed by a resonant soft x-ray scattering (RSoXS) at the carbon K-edge. The theoretical model shows that in case of a simple heliconical nematic structure two resonant signals corresponding to the full and half pitch band should be present, while only the full pitch band is observed in experiment. This suggests that the twist-bend nematic phase has complex structure with a double-helix, built of two interlocked, shifted helices. We confirm that the helical pitch in the twist-bend nematic phase is in a 10 nm range, for both, the chiral and achiral materials. We also show that the symmetry of a blue phase can unambiguously be determined through a resonant enhancement of x-ray diffraction signals, by including polarization effects, which are found to be an important indicator in phase structure determination.
Ewa Gorecka - One of the best experts on this subject based on the ideXlab platform.
-
structure of nanoscale pitch helical phases blue phase and twist bend nematic phase resolved by resonant soft x ray scattering
Soft Matter, 2017Co-Authors: Miroslaw Salamonczyk, Natasa Vaupotic, Damian Pociecha, Cheng Wang, Ewa GoreckaAbstract:Periodic structures of phases with orientational order of molecules but homogenous electron density distribution: a short pitch cholesteric phase, blue phase and twist-bend nematic phase, were probed by resonant soft X-ray scattering (RSoXS) at the carbon K-edge. The theoretical model shows that in the case of a simple heliconical nematic structure, two resonant signals corresponding to the full and half pitch band should be present, while only the full pitch band is observed experimentally. This suggests that the twist-bend nematic phase has a complex structure with a double-helix built of two interlocked, shifted helices. We confirm that the helical pitch in the twist-bend nematic phase is in a 10 nm range for both the chiral and achiral materials. We also show that the symmetry of the blue phase can be unambiguously determined through a resonant enhancement of the X-ray diffraction signals, by including polarization effects, which are found to be an important indicator in phase structure determination.
-
structure of nanoscale pitch helical phases blue phase and twist bend nematic phase resolved by resonant soft x ray scattering
arXiv: Soft Condensed Matter, 2017Co-Authors: Miroslaw Salamonczyk, Natasa Vaupotic, Damian Pociecha, Cheng Wang, Ewa GoreckaAbstract:Periodic structures of phases with orientational order of molecules, but homogenous electron density distribution: a short pitch cholesteric, blue phase and twist-bend nematic phase, were probed by a resonant soft x-ray scattering (RSoXS) at the carbon K-edge. The theoretical model shows that in case of a simple heliconical nematic structure two resonant signals corresponding to the full and half pitch band should be present, while only the full pitch band is observed in experiment. This suggests that the twist-bend nematic phase has complex structure with a double-helix, built of two interlocked, shifted helices. We confirm that the helical pitch in the twist-bend nematic phase is in a 10 nm range, for both, the chiral and achiral materials. We also show that the symmetry of a blue phase can unambiguously be determined through a resonant enhancement of x-ray diffraction signals, by including polarization effects, which are found to be an important indicator in phase structure determination.
Natasa Vaupotic - One of the best experts on this subject based on the ideXlab platform.
-
structure of nanoscale pitch helical phases blue phase and twist bend nematic phase resolved by resonant soft x ray scattering
Soft Matter, 2017Co-Authors: Miroslaw Salamonczyk, Natasa Vaupotic, Damian Pociecha, Cheng Wang, Ewa GoreckaAbstract:Periodic structures of phases with orientational order of molecules but homogenous electron density distribution: a short pitch cholesteric phase, blue phase and twist-bend nematic phase, were probed by resonant soft X-ray scattering (RSoXS) at the carbon K-edge. The theoretical model shows that in the case of a simple heliconical nematic structure, two resonant signals corresponding to the full and half pitch band should be present, while only the full pitch band is observed experimentally. This suggests that the twist-bend nematic phase has a complex structure with a double-helix built of two interlocked, shifted helices. We confirm that the helical pitch in the twist-bend nematic phase is in a 10 nm range for both the chiral and achiral materials. We also show that the symmetry of the blue phase can be unambiguously determined through a resonant enhancement of the X-ray diffraction signals, by including polarization effects, which are found to be an important indicator in phase structure determination.
-
structure of nanoscale pitch helical phases blue phase and twist bend nematic phase resolved by resonant soft x ray scattering
arXiv: Soft Condensed Matter, 2017Co-Authors: Miroslaw Salamonczyk, Natasa Vaupotic, Damian Pociecha, Cheng Wang, Ewa GoreckaAbstract:Periodic structures of phases with orientational order of molecules, but homogenous electron density distribution: a short pitch cholesteric, blue phase and twist-bend nematic phase, were probed by a resonant soft x-ray scattering (RSoXS) at the carbon K-edge. The theoretical model shows that in case of a simple heliconical nematic structure two resonant signals corresponding to the full and half pitch band should be present, while only the full pitch band is observed in experiment. This suggests that the twist-bend nematic phase has complex structure with a double-helix, built of two interlocked, shifted helices. We confirm that the helical pitch in the twist-bend nematic phase is in a 10 nm range, for both, the chiral and achiral materials. We also show that the symmetry of a blue phase can unambiguously be determined through a resonant enhancement of x-ray diffraction signals, by including polarization effects, which are found to be an important indicator in phase structure determination.
Xuming Zheng - One of the best experts on this subject based on the ideXlab platform.
-
Resonance Raman intensity analysis of the excited state proton transfer dynamics of 2-nitrophenol in the charge-transfer band absorption.
The Journal of chemical physics, 2006Co-Authors: Ya-qiong Wang, Huigang Wang, Shu-qiang Zhang, Ke-mei Pei, Xuming Zheng, David Lee PhillipsAbstract:Resonance Raman spectra were obtained for 2-nitrophenol in cyclohexane solution with excitation wavelengths in resonance with the charge-transfer (CT) proton transfer band absorption. These spectra indicate that the Franck-Condon region photodissociation dynamics have multidimensional character with motion along more than 15 normal modes: the nominal CCH bend+CC stretch nu(12) (1326 cm(-1)), the nominal CCC bend nu(23) (564 cm(-1)), the nominal CO stretch+NO stretch+CC stretch nu(14) (1250 cm(-1)), the nominal CCH bend+CC stretch+COH bend nu(15) (1190 cm(-1)); the nominal CCH bend+CC stretch nu(17) (1134 cm(-1)), the nominal CCC bend+CC stretch nu(22) (669 cm(-1)), the nominal CCN bend nu(27) (290 cm(-1)), the nominal NO(2) bend+CC stretch nu(21) (820 cm(-1)), the nominal CCO bend+CNO bend nu(25) (428 cm(-1)), the nominal CC stretch nu(7) (1590 cm(-1)), the nominal NO stretch nu(8) (1538 cm(-1)), the nominal CCC bend+NO(2) bend nu(20) (870 cm(-1)), the nominal CC stretch nu(6) (1617 cm(-1)), the nominal COH bend+CC stretch nu(11) (1382 cm(-1)), nominal CCH bend+CC stretch nu(9) (1472 cm(-1)). A preliminary resonance Raman intensity analysis was done and the results for 2-nitrophenol were compared to previously reported results for nitrobenzene, p-nitroaniline, and 2-hydroxyacetophenone. The authors briefly discuss the differences and similarities in the CT-band absorption excitation of 2-nitrophenol relative to those of nitrobenzene, p-nitroaniline, and 2-hydroxyacetophenone.
-
resonance raman intensity analysis of the excited state proton transfer dynamics of 2 nitrophenol in the charge transfer band absorption
Journal of Chemical Physics, 2006Co-Authors: Ya-qiong Wang, Huigang Wang, Shu-qiang Zhang, Xuming Zheng, David Lee PhillipsAbstract:Resonance Raman spectra were obtained for 2-nitrophenol in cyclohexane solution with excitation wavelengths in resonance with the charge-transfer (CT) proton transfer band absorption. These spectra indicate that the Franck-Condon region photodissociation dynamics have multidimensional character with motion along more than 15 normal modes: the nominal CCH bend+CC stretch ν12 (1326cm−1), the nominal CCC bend ν23 (564cm−1), the nominal CO stretch+NO stretch+CC stretch ν14 (1250cm−1), the nominal CCH bend+CC stretch+COH bend ν15 (1190cm−1); the nominal CCH bend+CC stretch ν17 (1134cm−1), the nominal CCC bend+CC stretch ν22 (669cm−1), the nominal CCN bend ν27 (290cm−1), the nominal NO2 bend+CC stretch ν21 (820cm−1), the nominal CCO bend+CNO bend ν25 (428cm−1), the nominal CC stretch ν7 (1590cm−1), the nominal NO stretch ν8 (1538cm−1), the nominal CCC bend+NO2 bend ν20 (870cm−1), the nominal CC stretch ν6 (1617cm−1), the nominal COH bend+CC stretch ν11 (1382cm−1), nominal CCH bend+CC stretch ν9 (1472cm−1). A pr...
-
a band resonance raman spectra of 1 2 diiodoethane in cyclohexane solution substituent effects on the 1 halo 2 iodoethane short time photodissociation dynamics
Chemical Physics Letters, 1998Co-Authors: Xuming Zheng, Yung Fong Cheng, David Lee PhillipsAbstract:Abstract Resonance Raman spectra of 1,2-diiodoethane in cyclohexane solution have been obtained in the A-band absorption. A resonance Raman intensity analysis was done to examine the short-time photodissociation dynamics of 1,2-diiodoethane. Significant bond length and bond angle changes were found for both C–I bonds and the C–C bond as well as the CCI and HCH bond angles. Comparison of the Franck–Condon region dynamics of 1,2-diiodoethane with diiodomethane suggests that the degree of coupling of the two C–I chromophores depends on both the relative geometry of the C–I bonds and their relative separation.
