Further results on the Aanderaa-Rosenberg conjecture

Some results on the “evasiveness” of graph properties are obtained, extending the work of Rivest and Vuillemin. In particular, it is shown that any nontrivial monotone graph property on n vertices is at least $\text{n}{}^2\text{9}\text{-}\text{evasive}$; particular stronger results are obtained for values of n that are powers of primes less than 14. A new result allowing interpolation among n values is obtained, as are some stronger results on restricted classes of properties.     

Metal benzoylpivaloylmethanates. Part II. 1,4-dioxane adducts of copper(II) chelates

Summary 1 : 1 Dioxane adducts of Copper(II) chelates withpara-subtituted benzoylpivaloylmethanes have been synthesized and their u.v., vis., i.r., mass, e.p.r. spectra as well as their magnetic moments and thermal stabilities investigated. Powdered samples of undiluted magnetically adducts were found to give well resolved e.p.r. spectra; the (S = 1) g_| signal being split into nine lines. Magnetic susceptibilities measured down to 4 K did not reveal exchange interactions. The uncommon structure of the e.p.r. spectra is believed to be due to the dimeric structure of the adduct in which an interion dipolar zero-field splitting of the triplet state occurs. The Cu-Cu distance estimated from the e.p.r. D_dd parameter is found to be 7.4 Å.     

Electronic spectra of the 2-oxypurine isomers

The Pariser-Parr-Pople type calculations were carried out for tautomeric isomers of 2-oxypurine. The calculated transition energies for the keto form (III) of this compound are in a good agreement with the observed absorption spectrum.     

Lifetimes and oscillator strengths of neutral vanadium

Oscillator strengths of 105 V(I) lines in the spectral range 2800–6000 Å were obtained by lifetime, emission, and hook measurements. Relative sets of ?-values were determined by combining emission measurements on a hollow cathode with hook measurements in a high temperature furnace, whereby no assumption concerning the plasma state is used and no temperature determination is required. The determination of the radiative lifetimes was performed by selective laser excitation of an atomic beam of vanadium and time-resolved observation of the reemitted fluorescence after the pulse. The absolute ?-values have an uncertainty of 12% on average. Both for the lifetimes and the ?-values a comparison with literature data is performed.     

Semi-empirical molecular orbital calculations for pyridinealdoximes and acetamidopyridines

Tautomerism of pyridinealdoximes and acetamidopyridines is discussed with regard to their electronic absorption spectra. The spectra of both neutral and ionic forms of the molecules are interpreted by means of the Pariser—Parr—Pople type of calculation in a satisfactory way.The stability of 2- and 4-pyridinealdoxime tautomers is investigated using the CNDO/2 method. The lactim are more stable than the lactam forms of the molecules. The molecules having the substituent group of the syn-configuration are more stable than the molecules with other configurations of the substituent.