The photoionization and photodissociative ionization processes of p-nitrotoluene(C,H,NO,) have been studied using the photoionization mass spectrometry wlth synchrotronradiation(SR) as the light source- The ionization...The photoionization and photodissociative ionization processes of p-nitrotoluene(C,H,NO,) have been studied using the photoionization mass spectrometry wlth synchrotronradiation(SR) as the light source- The ionization potential (PI) of p-nitrotoluene and eightappearance potentials(P.) of the ionic fragment from the SR photodissociative ionization ofC:H:NO, have been measured. Based on the mass spectra of C,H:NO, obtained with SR pho-tolonization and the relationship of energy in the processes, the most possible channels ofphotodissociative ionization of p-nltrotoluene have been analyzed.展开更多
The photoionization and photodissociation of bromoethane have been studied by using synchrotron radiation.The photoionization efficiency (PIE) curves of some fragments ions are measured.Based on these curves,the ioniz...The photoionization and photodissociation of bromoethane have been studied by using synchrotron radiation.The photoionization efficiency (PIE) curves of some fragments ions are measured.Based on these curves,the ionization potential of C 2H 5Br is determined to be 10.29eV,and the appearance potentials of C 2H 5 + ,CH 2Br +are measured to be 10.60eV,13.2eV respectively.We also have performed G2MP2 calculation on these fragments.According to experimental result and G2MP2 energy,the enthalpy of formation of ions C 2H 5 +,CH 2Br +,C 2H 5Br +,the bond energy of D 0(C 2H 5 +-Br),D 0(-Br),D 0(CH 2Br +-CH 3) have been evaluated.The most possible channels of the dissociation photoionization have been analyzed.展开更多
The 6H-pyridine clusters have been studied by the TOF mass spectrometry,the VUV from synchrotron rediation and the molecular beam technique three-type clusters are observed in the VUV photoionization mass spectroscopy...The 6H-pyridine clusters have been studied by the TOF mass spectrometry,the VUV from synchrotron rediation and the molecular beam technique three-type clusters are observed in the VUV photoionization mass spectroscopy: Pn+(n=2-5,P stands for6H-pyridine molecule), PnH+ (n=2-4) and Pn (H2O)m+(n=4,5, m=1;n=6, m=1,2). ThePnH+ clusters may have the chain structure,the Pn+ and Pn(H2O)m+ clusters may havethe cyclic structures, all of these are formed by the hydrogen-bond.展开更多
Photoionization and Photodissociation of epichlorohydrin are performed using a time-of-flight mass spectrometer（TOF-MS） with vacuum ultraviolet（VUV） photons from Hefei synchrotron radiation source. Photoionization...Photoionization and Photodissociation of epichlorohydrin are performed using a time-of-flight mass spectrometer（TOF-MS） with vacuum ultraviolet（VUV） photons from Hefei synchrotron radiation source. Photoionization mass spectrum and photoionization efficiency（PIE） curves of the fragment ions are measured. The appearance potentials of the fragment ions are obtained from their PIE curves. From these data, the formation enthalpies of some ions have been evaluated and their possible channels of dissociative photoionization have been discussed. The experimental results show that the mother ion of epichlorohydrin is unstable and the chlorine atom is easily lost to form ring C3H5O+ ion. Other fragment ions come from the dissociation of C3H5O+ ions.展开更多
Photoionization/dissociation of 1,2 propylene oxide are performed by using a time of flight mass spectrometer(TOF MS) with vacuum ultraviolet photons from Hefei synchrotron radiation source. The photoionization TOF ma...Photoionization/dissociation of 1,2 propylene oxide are performed by using a time of flight mass spectrometer(TOF MS) with vacuum ultraviolet photons from Hefei synchrotron radiation source. The photoionization TOF mass spectrum and photoionization efficiency(PIE) curves of fragment ions are measured.The appearance potentials(AP) of these ions are obtained from their PIE curves. From these data, the formation enthalpies of the observed ions have been evaluated, and their possible channels have been analyzed. The mechanism of dissociative photoionization of 1,2 propylene oxide has been discussed.展开更多
In this paper,the photoionization and photodissociative ionization processes of p aminoazobenzene (pAAB,C 12 H 11 N 3) using coincidence technology with vacuum ultraviolet synchrotron radiation (SR) photoionizaton mas...In this paper,the photoionization and photodissociative ionization processes of p aminoazobenzene (pAAB,C 12 H 11 N 3) using coincidence technology with vacuum ultraviolet synchrotron radiation (SR) photoionizaton mass spectroscopy are reported.The ionization potential (IP) of this molecule and the appearance potentials (AP) of the important ionic fragments from the SR photodissociative ionization of pAAB have been measured.On the basis of the IP(C 12 H 11 N 3) and AP measured in this experiment and the IP(C 6H 5) from the literature,the dissociative energy D 0(C 6H 5-N 2C 6H 4NH 2),D 0(C 6H + 5-N 2C 6H 4NH 2),D 0(C 6H 5-N 2C 6H 4NH + 2),D 0(C 6H 5N 2-C 6H 4NH + 2) and ionization potential of free radical N 2C 6H 4NH 2 have been evaluated.Based on the results of the mass spectroscopy of pAAB obtained with SR photoionization,the possible channels of photodissociative ionization of pAAB have been analyzed.The processes(molecular ions or the fregmental ions) giving rise to the ions C 6H + 5 and C 6H 6N + need further study.展开更多
The photoionization efficiency curve (PIE) of C2H3Cl+ formation from C2H3Cl hasbeen measured in wavelength region 105.0- 130.0nm, by using synchrotron radiation single- photonionization and a quadrupole mass spectrome...The photoionization efficiency curve (PIE) of C2H3Cl+ formation from C2H3Cl hasbeen measured in wavelength region 105.0- 130.0nm, by using synchrotron radiation single- photonionization and a quadrupole mass spectromemter as a detector. A series of peaks in region 106.0-117.0nm arise from Rydberg autoionization converging to A2A’ state of the vinyl chloride ion, theaverage quantum defects are δ(ns) = 1.87, δ(np) = 1.51,δ(nd) = 0.22 respectively. The Rydbergtransitions of π(2a") → 4d, π(2a") →5d, π(2a")→6s, π(2a") →7s have been assigned also.展开更多
The vacuum ultraviolet photoionization spectrum of Si(CH3)2Cl2 has been obtained with synchrotron radiation source. The adiabatic iomzation potential of Si(CHa)2Cl2 is 10.62±0.03eV (0.37eV lower than reported by ...The vacuum ultraviolet photoionization spectrum of Si(CH3)2Cl2 has been obtained with synchrotron radiation source. The adiabatic iomzation potential of Si(CHa)2Cl2 is 10.62±0.03eV (0.37eV lower than reported by PES), and the appearance potentials for Si(CH3)Cl2, Si(CH3)2Cl+, SiCH3+ and SiCl+ are 11.25±0.03eV,12.69±0.04eV, 15. 1±0.1eV and 21.16eV±0.1eV respectively. From these results, we estimate D(Si(CH3)Cl2+-CH3)=0.631±0.03eV and D(Si(CH3)2Cl+-Cl))=2.07±0.04eV.展开更多
文摘The photoionization and photodissociative ionization processes of p-nitrotoluene(C,H,NO,) have been studied using the photoionization mass spectrometry wlth synchrotronradiation(SR) as the light source- The ionization potential (PI) of p-nitrotoluene and eightappearance potentials(P.) of the ionic fragment from the SR photodissociative ionization ofC:H:NO, have been measured. Based on the mass spectra of C,H:NO, obtained with SR pho-tolonization and the relationship of energy in the processes, the most possible channels ofphotodissociative ionization of p-nltrotoluene have been analyzed.
文摘The photoionization and photodissociation of bromoethane have been studied by using synchrotron radiation.The photoionization efficiency (PIE) curves of some fragments ions are measured.Based on these curves,the ionization potential of C 2H 5Br is determined to be 10.29eV,and the appearance potentials of C 2H 5 + ,CH 2Br +are measured to be 10.60eV,13.2eV respectively.We also have performed G2MP2 calculation on these fragments.According to experimental result and G2MP2 energy,the enthalpy of formation of ions C 2H 5 +,CH 2Br +,C 2H 5Br +,the bond energy of D 0(C 2H 5 +-Br),D 0(-Br),D 0(CH 2Br +-CH 3) have been evaluated.The most possible channels of the dissociation photoionization have been analyzed.
文摘The 6H-pyridine clusters have been studied by the TOF mass spectrometry,the VUV from synchrotron rediation and the molecular beam technique three-type clusters are observed in the VUV photoionization mass spectroscopy: Pn+(n=2-5,P stands for6H-pyridine molecule), PnH+ (n=2-4) and Pn (H2O)m+(n=4,5, m=1;n=6, m=1,2). ThePnH+ clusters may have the chain structure,the Pn+ and Pn(H2O)m+ clusters may havethe cyclic structures, all of these are formed by the hydrogen-bond.
文摘Photoionization and Photodissociation of epichlorohydrin are performed using a time-of-flight mass spectrometer（TOF-MS） with vacuum ultraviolet（VUV） photons from Hefei synchrotron radiation source. Photoionization mass spectrum and photoionization efficiency（PIE） curves of the fragment ions are measured. The appearance potentials of the fragment ions are obtained from their PIE curves. From these data, the formation enthalpies of some ions have been evaluated and their possible channels of dissociative photoionization have been discussed. The experimental results show that the mother ion of epichlorohydrin is unstable and the chlorine atom is easily lost to form ring C3H5O+ ion. Other fragment ions come from the dissociation of C3H5O+ ions.
文摘Photoionization/dissociation of 1,2 propylene oxide are performed by using a time of flight mass spectrometer(TOF MS) with vacuum ultraviolet photons from Hefei synchrotron radiation source. The photoionization TOF mass spectrum and photoionization efficiency(PIE) curves of fragment ions are measured.The appearance potentials(AP) of these ions are obtained from their PIE curves. From these data, the formation enthalpies of the observed ions have been evaluated, and their possible channels have been analyzed. The mechanism of dissociative photoionization of 1,2 propylene oxide has been discussed.
文摘In this paper,the photoionization and photodissociative ionization processes of p aminoazobenzene (pAAB,C 12 H 11 N 3) using coincidence technology with vacuum ultraviolet synchrotron radiation (SR) photoionizaton mass spectroscopy are reported.The ionization potential (IP) of this molecule and the appearance potentials (AP) of the important ionic fragments from the SR photodissociative ionization of pAAB have been measured.On the basis of the IP(C 12 H 11 N 3) and AP measured in this experiment and the IP(C 6H 5) from the literature,the dissociative energy D 0(C 6H 5-N 2C 6H 4NH 2),D 0(C 6H + 5-N 2C 6H 4NH 2),D 0(C 6H 5-N 2C 6H 4NH + 2),D 0(C 6H 5N 2-C 6H 4NH + 2) and ionization potential of free radical N 2C 6H 4NH 2 have been evaluated.Based on the results of the mass spectroscopy of pAAB obtained with SR photoionization,the possible channels of photodissociative ionization of pAAB have been analyzed.The processes(molecular ions or the fregmental ions) giving rise to the ions C 6H + 5 and C 6H 6N + need further study.
文摘The photoionization efficiency curve (PIE) of C2H3Cl+ formation from C2H3Cl hasbeen measured in wavelength region 105.0- 130.0nm, by using synchrotron radiation single- photonionization and a quadrupole mass spectromemter as a detector. A series of peaks in region 106.0-117.0nm arise from Rydberg autoionization converging to A2A’ state of the vinyl chloride ion, theaverage quantum defects are δ(ns) = 1.87, δ(np) = 1.51,δ(nd) = 0.22 respectively. The Rydbergtransitions of π(2a") → 4d, π(2a") →5d, π(2a")→6s, π(2a") →7s have been assigned also.
文摘The vacuum ultraviolet photoionization spectrum of Si(CH3)2Cl2 has been obtained with synchrotron radiation source. The adiabatic iomzation potential of Si(CHa)2Cl2 is 10.62±0.03eV (0.37eV lower than reported by PES), and the appearance potentials for Si(CH3)Cl2, Si(CH3)2Cl+, SiCH3+ and SiCl+ are 11.25±0.03eV,12.69±0.04eV, 15. 1±0.1eV and 21.16eV±0.1eV respectively. From these results, we estimate D(Si(CH3)Cl2+-CH3)=0.631±0.03eV and D(Si(CH3)2Cl+-Cl))=2.07±0.04eV.
