Spin‐orbit excitation in the system I + I₂: Relativistically parameterized extended‐Hückel calculations

Abstract

Relativistically parameterized extended-Huckel (

Preparation, Crystal Structure, Vibrational Spectra, and Thermal Behavior of Tl2H2P2O6 and Tl4P2O6

“…The vibrational spectra of 2 are best interpreted by a [P 2 O 6 ] 4-unit, which behaves vibrationally with D 3d symmetry ( Table 2). [25] A vibrational analysis for such a [P 2 O 6 ] 4-unit delivers: [24,[26][27][28] …”

Photolysis of Matrix-Isolated HCl−Cl2 Complexes: Electronic Absorption and Emission Spectra Provisionally Assigned to Cl3

“…For example, formation of X 3 (X = Cl or I) has been suggested as the explanation for the high efficiency of X 2 as a third body in X atom recombination. , Transient I 3 formation is thought to be responsible for the large rate constant for the electronic to vibrational (E−V) transfer process I( 2 P 1/2 ) + I 2 −I( 2 P 3/2 ) + I 2 ( v >20) , and the efficient quenching of I 2 (A‘) by I 2 (I 2 (A‘) + I 2 (X) → I 3 + I) − …”

“…Following this work, Wright et al suggested that a 370−420 nm emission band, observed when Cl 2 was photodissociated under relatively high-pressure conditions, might also originate from Cl 3 . In parallel with the experimental efforts there have been many attempts to calculate potential energy surfaces for trihalogens using ab-initio ,− and semiempirical methods. ,− …”

“…6 Passage through bound trihalogen intermediates has also been used to explain the propensity for conservation of atomic electronic angular momentum (through spin-orbital symmetry conservation in the complex) in exchange reactions such as I( 2 P 1/2 ) + Br 2 f IBr + Br( 2 P 1/2 ), where the more exothermic process leading to Br( 2 P 3/2 ) is a minor channel. [7][8][9][10] To date, cross-beam scattering experiments have yielded the strongest evidence for the existence of bound trihalogens in the gas phase. I 2 F 11 and ClIF 12 resulting from F 2 + I 2 and F 2 + ICl reactions, and Br 3 from the photolysis of (Br 2 ) 2 dimers, 13 were detected by mass spectrometry.…”

“…In parallel with the experimental efforts there have been many attempts to calculate potential energy surfaces for trihalogens using ab-initio 15,[24][25][26] and semiempirical methods. 9,[27][28][29][30][31][32] Recently, additional interest in the trihalogens has been generated by novel time-resolved studies of the Br + I 2 reaction. 1,[33][34][35][36] From the results on this system, it appears that trihalogens, accessed through photodissociation of HX-YZ complexes, may be especially suitable for real-time studies of reaction dynamics.…”