Ionization energy measurements and spectroscopy of HfO and HfO+

Jeremy M. Merritt; Vladimir E. Bondybey; Michael C. Heaven

doi:10.1063/1.3098554

Ionization energy measurements and spectroscopy of HfO and HfO⁺

Jeremy M. Merritt, Vladimir E. Bondybey, Michael C. Heaven

Chair of Physical Chemistry

Emory University

Research output: Contribution to journal › Article › peer-review

14 Scopus citations

Abstract

Rotationally resolved spectra for the HfO⁺ cation have been recorded using the pulsed field ionization zero electron kinetic energy (PFI-ZEKE) technique. Resonant excitation of the F(0⁺)←X ¹∑⁺ band system of HfO was used as an intermediate level providing molecule and rovibrational state selectivity in the ionization process. The ionization energy (IE) of HfO, derived from the PFI-ZEKE spectrum, was determined to be 7.916 87(10) eV, which is 0.37 eV higher than the value reported from electron impact measurements. Underestimation of the IE in the previous studies is attributed to ionization of thermally excited states. A progression in the HfO⁺ stretch vibration up to v⁺ =4 was observed in the PFI-ZEKE spectrum, allowing for the determination of the ground electronic state vibrational frequency of ω_e⁺ =1017.7 (10) cm^-1 and anharmonicity of ω_ex _e⁺ =3.2 (2) cm^-1. The rotational constant of HfO+ was determined to be 0.403 (5) cm^-1. Benchmark theoretical ab initio calculations were carried out in order to explore the effects of electron correlation on the predicted molecular properties. Survey scans utilizing laser induced fluorescence and resonance enhanced multiphoton ionization detection revealed many previously unassigned bands in the region of the F-X and G-X bands of HfO, which we attribute to nominally forbidden singlet-triplet transitions of HfO.

Original language	English
Article number	144503
Journal	Journal of Chemical Physics
Volume	130
Issue number	14
DOIs	https://doi.org/10.1063/1.3098554
State	Published - 2009

Access to Document

10.1063/1.3098554

Cite this

@article{8d1ac2caefb6470badf618001f2f66f2,

title = "Ionization energy measurements and spectroscopy of HfO and HfO+",

abstract = "Rotationally resolved spectra for the HfO+ cation have been recorded using the pulsed field ionization zero electron kinetic energy (PFI-ZEKE) technique. Resonant excitation of the F(0+)←X 1∑+ band system of HfO was used as an intermediate level providing molecule and rovibrational state selectivity in the ionization process. The ionization energy (IE) of HfO, derived from the PFI-ZEKE spectrum, was determined to be 7.916 87(10) eV, which is 0.37 eV higher than the value reported from electron impact measurements. Underestimation of the IE in the previous studies is attributed to ionization of thermally excited states. A progression in the HfO+ stretch vibration up to v+ =4 was observed in the PFI-ZEKE spectrum, allowing for the determination of the ground electronic state vibrational frequency of ωe+ =1017.7 (10) cm-1 and anharmonicity of ωex e+ =3.2 (2) cm-1. The rotational constant of HfO+ was determined to be 0.403 (5) cm-1. Benchmark theoretical ab initio calculations were carried out in order to explore the effects of electron correlation on the predicted molecular properties. Survey scans utilizing laser induced fluorescence and resonance enhanced multiphoton ionization detection revealed many previously unassigned bands in the region of the F-X and G-X bands of HfO, which we attribute to nominally forbidden singlet-triplet transitions of HfO.",

author = "Merritt, \{Jeremy M.\} and Bondybey, \{Vladimir E.\} and Heaven, \{Michael C.\}",

note = "Funding Information: This work was supported by the U.S. Department of Energy under Grant No. DE-FG02-01ER15153-A005. We are indebted to Alexey Kaledin of the Emerson Center for Scientific Computing at Emory University for helping alleviate hardware limitations to performing the CCSDT calculations on HfO. We thank Kirk Peterson and Hermann Stoll for communicating preliminary results of calculations on using a newly developed ECP and basis set for Hf. We are also grateful to Michael Morse for pointing out that the resonances that produce intensity perturbations in the REMPI spectra are most probably encountered at the two-photon level of excitation. V.E.B. thanks die Deutsche Forschungsgemeinschaft for partial support of his visit to Emory University.",

year = "2009",

doi = "10.1063/1.3098554",

language = "English",

volume = "130",

journal = "Journal of Chemical Physics",

issn = "0021-9606",

publisher = "American Institute of Physics",

number = "14",

}

TY - JOUR

T1 - Ionization energy measurements and spectroscopy of HfO and HfO+

AU - Merritt, Jeremy M.

AU - Bondybey, Vladimir E.

AU - Heaven, Michael C.

N1 - Funding Information: This work was supported by the U.S. Department of Energy under Grant No. DE-FG02-01ER15153-A005. We are indebted to Alexey Kaledin of the Emerson Center for Scientific Computing at Emory University for helping alleviate hardware limitations to performing the CCSDT calculations on HfO. We thank Kirk Peterson and Hermann Stoll for communicating preliminary results of calculations on using a newly developed ECP and basis set for Hf. We are also grateful to Michael Morse for pointing out that the resonances that produce intensity perturbations in the REMPI spectra are most probably encountered at the two-photon level of excitation. V.E.B. thanks die Deutsche Forschungsgemeinschaft for partial support of his visit to Emory University.

PY - 2009

Y1 - 2009

N2 - Rotationally resolved spectra for the HfO+ cation have been recorded using the pulsed field ionization zero electron kinetic energy (PFI-ZEKE) technique. Resonant excitation of the F(0+)←X 1∑+ band system of HfO was used as an intermediate level providing molecule and rovibrational state selectivity in the ionization process. The ionization energy (IE) of HfO, derived from the PFI-ZEKE spectrum, was determined to be 7.916 87(10) eV, which is 0.37 eV higher than the value reported from electron impact measurements. Underestimation of the IE in the previous studies is attributed to ionization of thermally excited states. A progression in the HfO+ stretch vibration up to v+ =4 was observed in the PFI-ZEKE spectrum, allowing for the determination of the ground electronic state vibrational frequency of ωe+ =1017.7 (10) cm-1 and anharmonicity of ωex e+ =3.2 (2) cm-1. The rotational constant of HfO+ was determined to be 0.403 (5) cm-1. Benchmark theoretical ab initio calculations were carried out in order to explore the effects of electron correlation on the predicted molecular properties. Survey scans utilizing laser induced fluorescence and resonance enhanced multiphoton ionization detection revealed many previously unassigned bands in the region of the F-X and G-X bands of HfO, which we attribute to nominally forbidden singlet-triplet transitions of HfO.

AB - Rotationally resolved spectra for the HfO+ cation have been recorded using the pulsed field ionization zero electron kinetic energy (PFI-ZEKE) technique. Resonant excitation of the F(0+)←X 1∑+ band system of HfO was used as an intermediate level providing molecule and rovibrational state selectivity in the ionization process. The ionization energy (IE) of HfO, derived from the PFI-ZEKE spectrum, was determined to be 7.916 87(10) eV, which is 0.37 eV higher than the value reported from electron impact measurements. Underestimation of the IE in the previous studies is attributed to ionization of thermally excited states. A progression in the HfO+ stretch vibration up to v+ =4 was observed in the PFI-ZEKE spectrum, allowing for the determination of the ground electronic state vibrational frequency of ωe+ =1017.7 (10) cm-1 and anharmonicity of ωex e+ =3.2 (2) cm-1. The rotational constant of HfO+ was determined to be 0.403 (5) cm-1. Benchmark theoretical ab initio calculations were carried out in order to explore the effects of electron correlation on the predicted molecular properties. Survey scans utilizing laser induced fluorescence and resonance enhanced multiphoton ionization detection revealed many previously unassigned bands in the region of the F-X and G-X bands of HfO, which we attribute to nominally forbidden singlet-triplet transitions of HfO.

UR - http://www.scopus.com/inward/record.url?scp=65249179460&partnerID=8YFLogxK

U2 - 10.1063/1.3098554

DO - 10.1063/1.3098554

M3 - Article

AN - SCOPUS:65249179460

SN - 0021-9606

VL - 130

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

IS - 14

M1 - 144503

ER -

Ionization energy measurements and spectroscopy of HfO and HfO⁺

Abstract

Access to Document

Other files and links

Fingerprint

Cite this