We introduce a modification of reflectron time-of-flight mass spectrometer for laser photodissociation of mass-selected ions. In our apparatus, the ions of interests were selected by a mass gate near the first space f...We introduce a modification of reflectron time-of-flight mass spectrometer for laser photodissociation of mass-selected ions. In our apparatus, the ions of interests were selected by a mass gate near the first space focus point and decelerated right after the mass gate, were then crossed by a laser beam for dissociation. The daughter ions and surviving parent ions were re-accelerated and analyzed by the reflectron time-of-flight mass spectrometer. Compared to the designs reported by other research groups, our selection-deceleration-dissociation-reacceleration approach has better daughter-parent-ions-separation, easier laser timing, and better overlapping between the ion beam and laser beam. We also conducted detailed cal- culations on the parent ion and daughter ion flight times, and provided a simplified formula for the calibration of daughter ion mass.展开更多
Oxygen-poor vanadium oxide clusters, V2On＋ （n=l, 2）, V3On＋ （n=l, 2, 3）, and V4O3＋, were produced by laser vaporization and were mass-selected and photodissociated with 532 and 266 nm photons. The geometric stru...Oxygen-poor vanadium oxide clusters, V2On＋ （n=l, 2）, V3On＋ （n=l, 2, 3）, and V4O3＋, were produced by laser vaporization and were mass-selected and photodissociated with 532 and 266 nm photons. The geometric structures and possible dissociation channels of these clusters were determined based on the comparison of density functional calculations and pho- todissociation experiments. The experiments show that the dissociation of V2O＋, V2O2＋, and V3O3＋ mainly occurs by loss of VO, while the dissociation of V3O＋ and V4O3＋ mainly occurs by loss of V atom. For the dissociation of V3O2＋, the VO loss channel is slightly dominant compared to the V loss channel. The combination of experimental results and theoretical calculations suggests that the V loss channels of V3O＋ and V4O3＋ are single photon processes at both 532 and 266 nm. The VO loss channels of V2O2＋ and V3O3＋ are multiple-photon processes at both 532 and 266 nm.展开更多
基金V. ACKNOWLEDGMENTS This work supported by the National Natural Science Foundation of China （No.20853001）. We thank Professor Qi-he Zhu and Professor Zhen Gao for valuable discussions.
文摘We introduce a modification of reflectron time-of-flight mass spectrometer for laser photodissociation of mass-selected ions. In our apparatus, the ions of interests were selected by a mass gate near the first space focus point and decelerated right after the mass gate, were then crossed by a laser beam for dissociation. The daughter ions and surviving parent ions were re-accelerated and analyzed by the reflectron time-of-flight mass spectrometer. Compared to the designs reported by other research groups, our selection-deceleration-dissociation-reacceleration approach has better daughter-parent-ions-separation, easier laser timing, and better overlapping between the ion beam and laser beam. We also conducted detailed cal- culations on the parent ion and daughter ion flight times, and provided a simplified formula for the calibration of daughter ion mass.
基金This work was supported by the National Natural Science Foundation of China （No.20933008）. The theoretical calculations were conducted on the ScGrid and Deepcomp7000 of the Supercomputing Center, Com- puter Network Information Center of Chinese Academy of Sciences. We thank Dr. Xun-lei Ding and Dr. Yan-xia Zhao for valuable discussion.
文摘Oxygen-poor vanadium oxide clusters, V2On＋ （n=l, 2）, V3On＋ （n=l, 2, 3）, and V4O3＋, were produced by laser vaporization and were mass-selected and photodissociated with 532 and 266 nm photons. The geometric structures and possible dissociation channels of these clusters were determined based on the comparison of density functional calculations and pho- todissociation experiments. The experiments show that the dissociation of V2O＋, V2O2＋, and V3O3＋ mainly occurs by loss of VO, while the dissociation of V3O＋ and V4O3＋ mainly occurs by loss of V atom. For the dissociation of V3O2＋, the VO loss channel is slightly dominant compared to the V loss channel. The combination of experimental results and theoretical calculations suggests that the V loss channels of V3O＋ and V4O3＋ are single photon processes at both 532 and 266 nm. The VO loss channels of V2O2＋ and V3O3＋ are multiple-photon processes at both 532 and 266 nm.
