Core ionization of nitrosobenzene-dimer compounds: phenazon-di-N-oxide
Abstract The C 1s, N 1s and O 1s XPS spectra of soli d phenazon-di-N-oxide (PADNO) are presented in order to further elucidate the effects of intermolecular interactions in molecular solids on the dynamics of the core-ionization process. PADNO can be considered a model compound for an intramolecular cis nitrosobenzene dimer. The observed strong N 1s and O 1s shake-up intensity attenuations in going from the nitrosobenzene monomer to PADNO are discussed in detail based on the results of CNDO/S CI equivalent core calculations. The theoretical core-hole spectral functions are in excellent agreement with experiment. It is shown that the calculated shake-up intensities are strongly on electron correlation.
Comparison of core‐hole excitation spectra of organic donor/acceptor molecules in the vapor and condensed phases: p‐Nitroaniline, 2‐amino‐6‐nitronaphthalene, and 1‐amino‐4‐nitronaphthalene
Vapor phase N1s and O1s core‐hole spectra of the organic donor/acceptor molecules 2‐amino‐6‐nitronaphthalene (2,6‐ANN) and 1‐amino‐4‐nitronaphthalene (1,4‐ANN) are presented and compared to condensed phase results. 2,6‐ANN and 1,4‐ANN are found to exhibit broad single peak N1s(NO2) signals in the gas phase which become split into resolvable components in the solid. The spectral differences noted on going from the vapor phase to the solid parallel previous results on p‐nitroaniline (PNA). Unlike the situation encountered in PNA (and 2,6‐ANN), however, the O1s(NO2) spectrum of 1,4‐ANN also indicates a moderately increased splitting as well as an apparent decrease in shake‐up intensity on going from the vapor to the condensed phase. Spectral differences between the two phases are addressed within the CNDO/S(CI) equivalent‐core approximation including up to doubly excited ‘‘singlet‐coupled’’ configurations as a means of elucidating the apparent core‐hole induced intermolecular coupling. Comparison computations are presented on PNA, 2,6‐ANN, and 1,4‐ANN. X‐ray crystallographic measurements on 2,6‐ANN indicate an intermolecular donor/acceptor pairing scheme as in PNA. Dimer models are therefore used to computationally address solid state interactions. The N1s(NO2) spectral differences observed in PNA, 2,6‐ANN, and 1,4‐ANN on going from the vapor to the condensed phase are attributed to strong core‐hole induced intermolecular orbital mixing. Explicit inclusion of doubly excited configurations in both the monomer and dimer (solid) computations is essential to achieve theoretical assignments of the N1s(NO2) and O1s(NO2) spectra consistent with experiment. The results are analyzed in terms of dominant single and doubly excited contributions.
The Poet, The Critic, and the Moralist: Horace, Epistles 1.19
I begin by quoting from two valuable recent works on Horace. Professor Brink in his Horace on Poetry (1964) writes: ‘The centre of the short piece lies in lines 21—34. Readers, among them critics and poets, had denied one aspect of the Odes which was surely above criticism—the striking originality of these poems. Horace's defence turns on the question of originality’ (p. 180) and ‘Epistle 19 is unique in that it alone among the literary satires and letters reiterates Horace's claim to be the Latin fidicen’ (p. 182). And Dr. McGann in his Studies in Horace's First Book of Epistles (Collection Latomus 100: 1969): ‘In Ep. 19... as in the literary satires, Horace is a practising poet or at least a very recently practising one, engaged in defending himself against hostile criticism’ (p. 40) and ‘As the only epistle concerned exclusively with literary matters, the nineteenth stands apart’ (p. 82).