Resonant two-photon ionization spectroscopy of jet-cooled Pt?

Journal ArticleThe gas phase optical spectrum of jet-cooled Pt? has been investigated over the range of 11 300 to 26 300 cm -1 using resonant two-photon ionization spectroscopy in combination with time-of-flight mass spectrometry. Numerous vibronic bands are observed. Analysis of the data gives the location of some 26 excited electronic states, which are characterized by the frequencies of their origin bands, vibrational frequencies, and anharmonicities. Variation of the second color in a two-color resonant two-photon ionization scheme has determined the ionization threshold of Pt? to be 8.68 ?0.02 eV. The observation of the onset of predissociation, characterized by a sharp drop in excited state lifetime, places the dissociation energy of Pt? at 3.14?0.02 eV. In combination with the Pt atomic ionization potential of 8.8?0.2 eV, these results give the bond strength of Pt?+ as D0(Pt--Pt+) = 3.26 ? 0.24 eV. The strength of the chemical bond in Pt?, as compared to Au?, demonstrates that there are significant 5d contributions to the chemical bonding in Pt?

Spectroscopy and electronic structure of jet-cooled Al?

Journal ArticleResonant two-photon ionization spectroscopy has been used to study the jet-cooled Al? molecule. The ground state has been conclusively demonstrated to be of 3IIu symmetry, deriving from the ???rr?u electronic configuration. High resolution studies have established the bond length of the X?IIu state as re (X?IIu) = 2.701 ? 0.002 ?. The third-law estimate of the Al? bond strength has been reevaluated using the observed and calculated properties of the low-lying electronic states to give Do (Al?) = 1.34 ? 0.06 eV. In addition to the previously reported E 2 ??-g 2 ?X?IIu and F 3??-g ?X3IIu band systems, the E' 3?IIg ?X?IIu, F"-X, F'-X, G ?IIg ?X?IIu, H' ??-g ?X?IIU, and H??g ?X?IIu band systems have been observed for the first time. Bands of the G-X, H '-X, and H-X systems have been rotationally resolved and analyzed, providing rotational constants and electronic state symmetries for the upper states of these systems. A discussion of all of the experimentally known states of Al2 is presented, along with comparisons to previous experimental and theoretical work

Rydberg and pulsed field ionization-zero electron kinetic energy spectra of YO

Journal ArticleA spectroscopic study of the Rydberg states of YO accessed from particular rotational levels of the A 2II1/2, v=0 state has been combined with a pulsed field ionization, zero electron kinetic energy (PFI-ZEKE) investigation. The results provide accurate values of the ionization energy of YO, ionization energy I.E.(YO)=49 304.316(31) cm-1 [6.112 958](4) eV], and of the rotational constant (and bond length) of the YO+ cation in its X 1?+, v=0 ground state, B0+=0.4078(3) cm21 [r0=1.7463(6) ?]. The improved value of I.E.(YO) combined with the known ionization energy of atomic yttrium then leads to the result D0 0 (Y+-O)2D0 0 (Y2O=0.1041?0.0001 eV. Combining this result with the value of D0 0 (Y+-O) obtained from guided ion beam mass spectrometry yields an improved value of D0 0 (Y+O)=7.14?0.18 eV. The PFI-ZEKE spectra display an interesting channel-coupling effect so that all rotational levels with J+?J'(A)+0.5 are observed with high intensity, where J+ is the angular momentum of the YO+ cation that is produced and J'(A) is the angular momentum of the A 2II1/2 state that is reached when the first photon is absorbed. This is thought to result from the interaction between the dipole moment of the rotating YO+ core and the Rydberg electron, which can induce changes in l and J+ subject to the dipolar coupling matrix element selection rule, ?J+=?1, ?l=?1. The channel-coupling mechanism also appears to induce an inverse autoionization process in which an unbound electron with a low value of l is captured either by its low-J+1 YO+ cation or by a second YO+ cation with the same value of J+. This inverse autoionization process is extremely sensitive to the electron kinetic energy, leading to narrow peaks in the PFI-ZEKE spectrum which are only slightly broader than the laser linewidth employed for this study (0.25 cm-1)

Spectroscopy of diatomic ZrF and ZrCl: 760 ? 555 nm

Journal ArticleThe optical spectrum of diatomic ZrF has been investigated, with transitions recorded in the range from 14 700 to 18 000 cm?1. Many bands have been observed, several of which can be grouped into three band systems. Rotationally resolved investigations are hampered by perturbations that are rampant among the excited states, but three unperturbed bands have revealed that the ground state of ZrF has ?" = 3/2, with a bond length of r"e = 1.854(1) ?. Hot bands originating from v" = 1 provide the ground state vibrational interval, ?G"1/2 = 691.45(2) cm?1 for 90Zr19F. Based on comparisons to ZrCl and ligand-field considerations, the ZrF ground state is assigned as a 2?3/2 level deriving from the 3?2 1?1 configuration, in agreement with a previous study. In addition to the measurements on ZrF, vibronically resolved spectra of ZrCl have been recorded over the 13 000 to 18 000 cm?1 range, and four band systems have been identified