W. Robert Carper

DFT models of molecular species in carbonate molten salts

Raman spectra of high temperature carbonate melts are correlated with carbonate species modeled at 923 K using B3LYP/(6-311+G(2d,p)) density functional calculations. Species that are theoretically stable at 923 K include O(2-), O(2)(-), O(2)(2-), CO(3)(2-), C(2)O(6)(2-), CO(4)(-), CO(4)(2-), CO(4)(4-), CO(5)(2-), KCO(4)(-), LiCO(4)(-), KO(2)(-), LiO(2)(-), NaO(2)(-), KO(2), LiO(2), NaO(2), KCO(3)(-), LiCO(3)(-), and NaCO(3)(-). Triangular, linear, and bent forms are theoretically possible for KO(2)(-) and NaO(2)(-). Triangular and linear forms may exist for LiO(2)(-). Linear and triangular versions are theoretically possible for LiO(2)(-) and KO(2). A triangular version of NaO(2) may exist. The correlation between measured and theoretical Raman spectra indicate that monovalent cations are to be included in several of the species that produce Raman spectra.

Radiative lifetime of the Te2 B0+u and A0+u states excited by a pulsed dye laser

Abstract A pulsed dye laser has been used to measure the radiative lifetimes and quenching rates of transitions of the B0+u and A0+u states of Te2. The observed zero pressure lifetimes vary from 55 to 730 ns. The quenching rates vary from 0.9 × 106 to 40 × 106 s−1 Torr−1.

Chemiluminescent reaction of selenium with fluorine: Assignment of the SeF A 2Π3/2 state

Selenium reacts with fluorine with a weak visible chemiluminescence between 3800 and 8900 A. Identical spectra are obtained regardless of whether the source of selenium is the elemental vapor or hydrogen selenide. By analogy with C10, TeF, and reevaluated SF absorption data, the SeF band system is assigned to transitions between inverted 2Π states. The spectroscopic constants for the A 2Π3/2 to X 2Π3/2 system are: Te=14 680.4 cm−1, ω‘e =688.8 cm−1, ωex‘e =1.84 cm−1, ω’e =444.1 cm−1, and ωexe =2.93 cm−1. The weak 2Π1/2 to 2Π1/2 subband is described by the constants: Te =15 025.4 cm−1, ω‘e =683.0 cm−1, ωex‘e =2.11 cm−1, ω’e =436.9 cm−1, and ωexe =1.20 cm−1. Laser excitation spectra were recorded for the SeF chemiluminescence flame. The SeF fluorescence between 4200 and 5200 A is rapidly quenched with increasing total pressure. A Stern–Volmer analysis gave a zero pressure lifetime of 12.8±3.9 μs. The measured quenching rate of 2.5×106 s−1 Torr−1 is nearly gas kinetic.

Dual spin probe NMR relaxation studies of ionic structure in 1-ethyl-3-methylimidazolium chloride-AlCl3 molten salts

Abstract Room temperature molten salts consisting of 1-ethyl-3-methylimidazolium chloride (MEICl), AlCl 3 and NaCl are of interest as electrochemical agents. Results of 27 Al and 13 C NMR dual spin probe (DSP) relaxation studies of these ionic ligands support the existence of interactions between MEI + and AlCl 4 − . The dual spin probe method is used to determine liquid state quadrupole coupling constants of 0.821 and 2.10 MHz for the neutral (MEIClAlCl 3 ) and neutral buffered (Na + 0.22 MEI + 0.78 AlCl 4 − ) melts.

Multiple spin probe NMR studies of ionic structure in 1-methyl-3-ethylimidazolium chloride-AlCl3 molten salts

Abstract The microdynamics of a room temperature molten salt system consisting of 1-methyl-3-ethylimidazolium chloride (MEICI), AlCl 3 and NaCl is investigated by 13 C, 23 Na and 27 Al NMR relaxation methods and viscosity measurements. This study supports the existence of a complex containing MEI + , AlCl 4 − and Na + . The dual spin probe (DSP) method is extended to 23 Na, which has a liquid state quadrupole coupling constant of 1.0 MHz in this complex.

Chemiluminescent reaction of tellurium with fluorine: The A 2Πi–X 2Πi and B 2Σ+–X2Πi transitions

Te reacts with fluorine to give a strong chemiluminescence between 3800 and 8700 A. The emission spectrum contains both 2Σ+–2Πi and 2Πi–2Πi systems. TeF emission bands are of the Hund’s type (a) without spin forbidden intermultiplet crossing. Spin orbit coupling of the X 2Πi state is −497 cm−1 as determined from the 2Σ+–2Πi transition. Vibrational constants are reported for all states and compare favorably with those obtained from theory.