The kinetic processes of the photoionization and dissociation of 4H-furan have been investigated by using synchrontron radiation. The IP of 4H-furan and APs of other lons are gotten from the spectra,the possible channels of dissociative photoionization have been annalyzed. A serices of stable clusters composed of (THF)n. (H2O)n-2H+ (n=2,3,4,5) are present in the MS and the possible structures of the clusters are given.
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.
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.
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.
The photoionization and photodissociative ionization processes of azoxybenzene (C12H10N2O,AOB) have been studied using the photoionization mass spectrometry with vacuum ultraviolet synchrotron radiation (SR) as the light source. The ionization potential (IP) of this molecule and four appearance potentials (AP) of the important ionic fragments from the SR photodissociative ionization of AOB have been measured. On the basis of the IP(C12H10N2O) and AP() measured in this experiment,the dissociative energy D0(-N2OC6H5) has been evaluated. Based on the results of the mass spectroscopy of AOB,the possible channels of photodissociative ionization of AOB have been analyzed.
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.
