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This paper summarizes the results of studies on the formation of negative ions by the electronic bombardment of polyatomic molecules. The compounds studied include cyanogen, methyl cyanide, carbon tetrachloride, carbon tetrafluoride and various fluorochloromethanes. It has been found that these compounds can be grouped into two classes depending on the ways they form negative ions, Class I consists of molecules like cyanogen and methyl cyanide which form negative ions largely by a resonance capture process of the type XY + e = X + Y-. Class I1 comprises compounds, of which carbon tetrachloride is a typical example, from which negative ions are formed by the resonance capture process, and also by an ion pair process namely XY + e = X+ + Y-+ e.Examples of these processes are discussed in detail and the mechanism of the formation of negative ions is considered. With the CN-ion, consideration of its electron structure leads to the conclusion that it should be quite stable. It is also shown that this ion is probably formed with considerable excess kinetic energy.

The ionization and dissociation of cyanogen and methyl cyanide have been studied in a mass spectrometer. Appearance potential measurements have been made on a number of the ions formed and probable dissociation processes are discussed in some detail. The formation of CN negative ions by electron bombardment of both cyanogen and methyl cyanide is shown to occur entirely by resonance capture processes. A method for determining the appearance potentials of negative ions is discussed and used to assess the voltage at which CN negative ions are produced in both compounds.Since CN negative ions are produced from methyl cyanide only by a resonance capture process it follows that the dissociation process leading to the formation of CH3+ ions must be CH3CN + e = CH3+ + CN $-2e. Measurement of the appearance potential of the CH3+ ion from methyl cyanide allows us to calculate D(CH3-CN) and this datum with relevant thermochemical information enables us to estimate the heat of formation of the CN radical. Knowledge of this value makes it possible to calculate the dissociation energy of the carbon-carbon bond in cyanogen and the dissociation energy of the CH bond in hydrogen cyanide.

Women may be particularly vulnerable to alcohol harm, but many current theories fail to acknowledge the unique factors that influence female alcohol use. The biological mechanisms underlying female alcohol consumption have largely been unexplored, although recently the menstrual cycle has been highlighted as a potentially important factor. This systematic review, using a narrative synthesis, examined the association between the menstrual cycle phases on alcohol consumption and aimed to determine whether hormonal contraception influences this association. The review follows PRISMA and SWiM guidelines, registration number: CRD42018112744. Electronic searches were conducted in the relevant databases with keyword (e.g., “menstrua*”; “alcohol”). Thousand six hundred and sixty-two titles were identified, 16 of which were included in the review. Results were inconsistent regarding whether an association between menstrual cycle phase and alcohol consumption was found. Furthermore, there was inconsistency regarding which phase was associated with higher consumption, and different factors were reported to have moderated the direction, e.g., family history of alcohol use disorder (AUD), premenstrual syndrome (PMS). These conflicting results may be partly explained by variability in both study quality and design, and differences in measurement of cycle phase and alcohol consumption. More robust research is needed before conclusions can be drawn with regard to the role of the menstrual cycle and hormonal contraception on female drinking behavior. This review provides recommendations to strengthen research in this area.