Some Observations on the Spectra of the Diatomic Fluorides of Silicon, Germanium, Tin, and Lead

Cationic Germanium Fluorides: A Theoretical Investigation on the Structure, Stability, and Thermochemistry of GeFn/GeFn+ (n = 1−3)

“…i CASSCF/second-order CI + Q with no ZPE, ref . j From the study of the Rydberg states of GeF, ref b. k From mass spectrometric measurements, ref a.…”

“…The properties of neutral germanium fluorides GeF n ( n = 1−5) have been intensively investigated over the years by various experimental and theoretical methods, − not only for fundamental reasons but also for their active role in the fine processing of semiconductors. − More recently, the structure, stability, and thermochemistry of the corresponding anionic species GeF n - ( n = 1−5) have been systematically investigated by density functional methods, and discussed in connection with previous related experimental and theoretical data. 3j,k,− ,− As for cationic germanium fluorides, experimental and theoretical studies 55a,61 indicate that, in the ground state, GeF 4 + is unstable and prone to dissociate into GeF 3 + and atomic fluorine. On the other hand, all the other ground-state GeF n + ( n =1−3) are quite stable in the gas phase and abundantly detected, for example, from the electron impact fragmentation of GeF 4 55a.…”

“… The structure, harmonic frequencies, enthalpies of formation, and dissociation energies of the GeF n + cations ( n = 1−3) and of their neutral counterparts GeF n have been investigated at the MP2 and CCSD(T) levels of theory and discussed in connection with previous experimental and theoretical data. The CCSD(T,full)/cc-pVTZ-optimized geometries and MP2(full)/6-311G(d) harmonic frequencies are 1.744 Å and 668.0 cm -1 for GeF( 2 Π), 1.670 Å and 798.6 cm -1 for GeF + ( 1 Σ + ), 1.731 Å/97.4° and 267.0 (a 1 )/673.1 (b 2 )/690.6 (a 1 ) cm -1 for GeF 2 ( C 2 v ,A 1 ), 1.666 Å/116.9° and 202.3 (a 1 )/769.6 (a 1 )/834.6 (b 2 ) cm -1 for GeF 2 + ( C 2 v ,A 1 ), 1.706 Å/112.2° and 214.4 (e)/273.1 (a 1 )/699.6 (a 1 )/734.1 (e) cm -1 for GeF 3 ( C 3 v , 2 A 1 ), and 1.644 Å and 211.4 (e‘)/229.9 (a 2 ‘ ‘)/757.4 (a 1 ‘)/879.3 (e‘) cm -1 for GeF 3 + ( D 3 h , 1 A 1 ). These calculated values are in excellent agreement with the experimental data reported for GeF, GeF + , and GeF 2 , and should be therefore of good predictive value for the still unexplored GeF 2 + , GeF 3 , and GeF 3 + .…”

Resonance enhanced multiphoton ionization spectroscopy of the SnF radical

“…The SnF radical has been the subject of several spectroscopic studies in the wavelength region 330-200 nm ͑30 300-50 000 cm Ϫ1 ͒, [1][2][3][4][5][6][7][8] giving information on eight doublet electronic states including the ground state. The ground state is a 2 ⌸ state with a spin-orbit splitting constant of 2316.9 cm Ϫ12 and a valence shell electronic configuration of 1 2 2 2 3 2 1 4 2 1 , with the 2 electron concentrated mainly on the Sn atom.…”

“…8 The amount of data on the excited states varies, with several systems having been rotationally analyzed ͑the A 2 ⌺ ϩ -X 2 ⌸ and B 2 ⌺ ϩ -X 2 ⌸ systems, 3 and the C 2 ⌬ -X 2 ⌸ and C 2 ⌬ -X 2 ⌸ systems 4 .͒ Other transitions are less well characterized, although vibrational frequencies have been determined for the E 2 ⌸ and F 2 ⌺ ϩ states. 2 Nothing is known of the character of the D state. Melen and Dubois 7 have classified these various states as being either Rydberg ͓in the case of the B 2 ⌺ ϩ 6S←2 transition͒, E 2 ⌸ ͑6p←2͒, F 2 ⌺ ϩ ͑7s←2͒ and G 2 ⌬ ͑5d␦←2͒ states͔ or valence states ͑in the case of the A 2 ⌺ ϩ , C 2 ⌬, and D states͒.…”