Infrared Absorption Spectrum of Meta - Bromo Benzonitrile in Liquid State

Abstract

The infrared absorption spectrum of m-bromobenzonitrile in the liquid state has been obtained in the region 250–4000 Cm^?1. The spectrum has been interpreted in detail, assuming that the molecule has C symmetry and the assignments of the various fundamental vibrations have been made accordingly.     

Vibrational Spectrum of Para-Fluoro Phenetole

Abstract

The 400–4000 Cm^?1infrared absorption apectrum of p-fluoro phenetole molacule in liquid phase is reported. The observed spectrum is interpreted on the assumption that the melecule has C₂ symmetry together with the assignments of the fundamental vibrations to various probable modes of vibrations.     

The Effect of Intramolecular Hydrogen Bonding on the Intensity and Frequency of OH Stretching Band in Alicyclic Substances

The change in intensity and frequency of O-H stretching band upon intramolecular hydrogen bonding was sufficiently examined for various proton acceptors of many alicyclic substances. The order of proton acceptors to bring about the intensity increase of constant degree is: Some discussions are given on these.     

Electronic Spectra and Structure of p-Benzoquinone

Ground and excited state electronic structure and spectra of p-benzocuinone have been studied using the variable electronegativity SCF-MO-CI method. The calculated values of ionization potential and excitation energies are in good agreement with experiment. It is found that the electronic structure and geometry of the molecule are appreciably different in the excited singlet state as compared to the ground state.     

Structural phase transitions at clean and metal-covered Si(111) surfaces investigated by RHEED spot analysis

Structural phase transitions between various kinds of superlattice structures formed on a Si(111) surface have been investigated by spot analysis of reflection high-energy electron diffraction (RHEED). Reversible transitions induced by temperature changes and irreversible ones induced by metal depositions were observed. Detailed discussions on the dynamics of the phase transitions are made by quantitative analyses of integrated spot intensity and profile. For a phase transition of 7′7  1′1 structures on a clean Si(111) surface, a hysteresis with temperature difference of 5°C. between in heating and cooling processes was found in the spot intensity change, indicating a first-order transition. Hysteresis was hardly recognized, on the other hand, for transitions of Au-induced superstructures (5×2-Au or ×-Au)  1×1-Au. The spot profiles were found to be broadened during the transition of Si(111)-×-Au  1×1-Au, which was a signature of a continuous transition, while the profiles remained unchanged during the transitions of the 7×7  1×1 and 5×2-Au  1×1-Au phases. Structural conversions induced by In adsorption on the Si(111) surface kept at constant temperatures were also analyzed. The conversions at room temperature were totally dependent on the initial substrate surface structures; the 7×7 surface did not show any structural conversion with In adsorption, while the ×-In surface successively converted to a 2×2 and a × phase with coverage increase. The structural transitions at elevated temperatures were sensitively dependent on the temperatures. Sequences of transitions among the 7×7, 4×1, ×, 1×, and ×4 were quantitatively revealed as changes in RHEED spot intensity.