Molecular beam photoionization study of HgBr/sub 2/ and HgI/sub 2/

Journal Article · Sat Jan 01 00:00:00 EST 1983 · J. Chem. Phys.; (United States)

OSTI ID:6635298

Linn, S H; Tzeng, W; Brom, Jr, J M; Ng, C Y

Photoionization efficiency (PIE) data for HgBr/sub 2//sup +/ and HgI/sub 2//sup +/ and their fragment ions have been obtained in the region 600--1350 A using an oven-type supersonic beam source. The ionization energies (IE) for the X /sup 2/Pi/sub 3/2g/ states of HgBr/sub 2//sup +/ and HgI/sub 2//sup +/ were determined to be 10.560 +- 0.003 and 9.5088 +- 0.0022 eV, respectively. The analyses of the Rydberg series converging to the /sup 2/Pi/sub 1/2g/ states of HgBr/sub 2//sup +/ and HgI/sub 2//sup +/ yield a value of 10.8846 +- 0.0012 eV for the IE of the /sup 2/Pi/sub 1/2g/ state of HgBr/sub 2//sup +/ and 10.1953 +- 0.0025 eV for that of HgI/sub 2//sup +/. The major fragment ions from HgBr/sub 2/ were identified to be HgBr/sup +/, Hg/sup +/, Br/sub 2//sup +/, and Br/sup +/ and those from HgI/sub 2/ were found to be HgI/sup +/, I/sub 2//sup +/, and I/sup +/. The measured appearance energies for HgBr/sup +/ and HgI/sup +/ allow the calculation of the bond dissociation energies for HgBr/sup +/ and HgI/sup +/ to be 55 +- 2 and 59 +- 1 kcal/mol, respectively. Similar to the observation in the PIE curves for HgCl/sub 2//sup +/ and its fragment ions, the PIE spectra for HgBr/sub 2//sup +/, HgI/sub 2//sup +/, and their fragment ions are dominated by autoionization structures exhibiting asymmetric Beutler--Fano line profiles. The comparison of the PIE curves of HgCl/sub 2//sup +/, HgBr/sub 2//sup +/, HgI/sub 2//sup +/, and Hg/sup +/ from Hg confirms the previous conclusion that these autoionizing Rydberg series can be assigned to transitions((5d)/sup 10/sigma/sub g//sup 2/sigma/sub u//sup 2/..pi../sub u//sup 4/..pi../sub g//sup 4/) ..-->.. ((5d)/sup 9/sigma/sub g//sup 2/sigma/sub u//sup 2/..pi../sub u//sup 4/..pi../sub g//sup 4/ /sup 2/D/sub plus-or-minus5/2/)np and ((5d)/sup 10/sigma/sub g//sup 2/sigma/sub u//sup 2/..pi../sub u//sup 4/..pi../sub g//sup 4/) ..-->.. ((5d)/sup 9/sigma/sub g//sup 2/sigma/sub u//sup 2/..pi../sub u//sup 4/..pi../sub g//sup 4/ /sup 2/D/sub plus-or-minus3/2,tsplus-or-minus1/2/)np, n> or =6, which are mainly associated with the mercury atom in HgX/sub 2/, X = Cl, Br, and I.

• Research Organization: Ames Laboratory, U.S. Department of Energy, and Department of Chemistry, Iowa State University, Ames, Iowa 50011
• OSTI ID: 6635298
• Journal Information: J. Chem. Phys.; (United States), Vol. 78:1
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
MERCURY BROMIDES
PHOTOIONIZATION
MERCURY IODIDES
DISSOCIATION
EFFICIENCY
MOLECULAR BEAMS
BEAMS
BROMIDES
BROMINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
IODIDES
IODINE COMPOUNDS
IONIZATION
MERCURY COMPOUNDS
MERCURY HALIDES
640302* - Atomic
Molecular & Chemical Physics- Atomic & Molecular Properties & Theory