William E. Jones

The spectra and structure of indium iodide: the rotational and vibrational constants of the B 1 state

Abstract The rotational constants of the B 1 state of indium iodide are reported for the first time as B e = 0.037533 cm −1 and α e = 0.000289 cm −1 while T e = 25050.60 cm −1 for the B 1- X 0 + transition. Accurate vibrational constants are also computed from measured Q heads as ω e = 146.36 cm −1 and ω e χ e = 2.20 cm −1 .

The electronic spectrum of bismuth monofluoride: A reinvestigation of the A0+-X10+ system

Abstract A reinvestigation of the A 0 + - X 1 0 + band system, the most electronic transitions reported for bismuth monofluoride, is presented. Approximately 65 bands were photographed in emission between 4220 and 5417 A, of which 33 were rotationally analyzed. Inconsistencies in earlier vibrational analyses were resolved. Rotational constants for 0 ≤ ν ′ ≤ 12 and 0 ≤ ν ″ ≤ 18 were determined from direct least-squares fitting to the measured line positions of each band. “Merging” of the overdetermined constants was performed to obtain the best single estimate of each parameter. The resulting minimum-variance linear unbiased estimates were used to calculate RKR potential curves. Franck-Condon factors and r centroids were subsequently obtained and are presented. Evidence is given for predissociation in the upper state; perturbations involving levels above the crossing point are correlated with those previously reported in the B 0 + state. The upper limit of the ground-state dissociation energy (3.14 eV) is in accord with extrapolated values as given in earlier investigations. The nature of a postulated third interacting state is also discussed.

Geometries, energies and polarities of cyanopolyynes.

Abstract Single determinant ab initio molecular orbital theory has been applied to the description of the equilibrium geometries, total energies, atomization energies, force constants, dipole moments and total atomic charges of the first five cyanopolyynes, H(CC) n CN. Hydrogen cyanide and acetylene are included for comparison. In order to study the basis set dependence of the computed properties, three methods of introducing more flexibility into the STO-3G minimal basis set have been considered: increasing the number of primitives, introducing split-valence basis sets and adding polarization functi The mean absolute deviation between the theoretical and observed bond lengths decreases along the series STO-3G, STO-6G, 3-21G, 4-31G and 6-31G. The relatively new 3-21G split-valence basis set leads to the best agreement with the experimental dipole moments. At the STO-NG level the net atomic charg and equilibrium bond lengths are observed to tend monotonically, as a function of chain length, to certain asymptotic values. Due to cancellation of errors in the CC and CC bond lengths, the STO-3G basis set yields estimates of the rotational constant, B e , for the larger cyano which are expected to be too large by about 0.6%.

The b0+-X21 and b0+-X10+ bands of SbF

Abstract In the emission spectrum of the SbF molecule a new band system is recorded in the near infrared. The rotational analysis of these new bands shows that they belong to the b 0 + - X 2 1 and b 0 + - X 1 O + transitions and yields molecular constants for the states involved. This new information, together with improved vibrational analyses of the B and C 1 systems, permits the electronic energy diagram of the SbF molecule to be derived.

The spectra and structure of indium iodide: potential energy curves and dissociation energies of the X 0+, A 0+, and B 1 states

Abstract Rotational constants for the A 0 + and B 1 states reported previously have been slightly revised as a result of the analysis of a further sixteen bands in the A 0 + - X 0 + and B 1- X 0 + band systems. Potential energy curves have been constructed on the basis of the revised molecular constants. A discussion of the nature of the chemical bond in InI and the possible correlation to dissociation products has led to a revised value of 27 500 cm −1 for the dissociation energy of ground state InI.

Rotational analysis of the A0+-X0+ and B1-X0+ systems of indium bromide

Abstract The rotational analysis of the 0-0 bands of the A 0 + - X 0 + and B 1- X 0 + systems of indium bromide is reported. The rotational constants have been determined as B v =0 = 0.058314 and B v =0 = 0.058149 cm −1 for the A 0 + and B 1 states of In 79 Br and B v =0 = 0.057454 and B v =0 = 0.057297 cm −1 for the A 0 + and B 1 states of In 81 Br.

The electronic spectrum of bismuth monofluoride: An 0+ ← X10+ band system at 3838 Å

Abstract Emission bands of BiF (in the region of 3800 A), formerly designated as belonging to the B - X 1 0 + and A 3 - X 1 0 + transitions, have been photographed and rotationally analyzed under high resolution. These bands have been found to belong to an 0 + ← X 0 + system. Extensive rotational and vibrational perturbations have been observed and the nature of the perturbing state is discussed.

Spectroscopic investigation of InCl in the ultraviolet: Constants of the A3Π0 state

Abstract The emission spectrum of InCl has been photographed at a dispersion of approximately 0.13 A/mm. The rotational structure of eleven bands in the region 3500–3740 A, belonging to the A3Π0-X1Σ+ system has been analyzed and accurate equilibrium rotational constants for the A3Π0 state are reported for the first time as follows: B′ e =0.11523 cm −1 α′ e =0.00067 cm −1 D′ e =5.53 × 10 −8 cm −1 The rotational analysis has provided accurate band origins for the eleven bands analyzed, and has allowed the presentation of more accurate vibrational constants for the A3Π0 and X1Σ+ states than previously available. Several perturbations in the v = 0 and 1 levels of the A3Π0 state are observed.

Photolysis of 3-chloro-3-methyldiazirine

Abstract Photolysis of 3-chloro-3-methyldiazirine through glass gives vinyl chloride, acetylene, hydrogen chloride and nitrogen as products. The mechanism proposed is that of Frey and Stevens for photolysis of 3-methyl- diazirine. In addition 1,1-dichloroethane is formed. Photolysis with added hydrogen bromide leads to the formation of 1-bromo-1-chloroethane

Rotational analysis of the 1Π-X1Σ+ system of AsN☆

Six bands of the strongly perturbed 1Π-X1Σ+ system of AsN have been photographed with a dispersion of approximately 0.4A/mm. rotational constants found for the lower state are, Be″ = 0.5457 cm−1, D″ = 5.7 × 10−7 cm−1, αe″ = 0.0037 cm−1, and re = 1.618 A, while for the upper state the values are Be′ = 0.5018 cm−1, D′ = 6.6 × 10−7 cm−1, αe′ = 0.009 cm−1, and re = 1.687 A. Approximate B values for two of the perturbing states have been found to be 0.34 and 0.43 cm−1.