Andrew Inchley

New apparatus for liquid sampling in electron spectroscopy: He(I) spectra of the vapours and surfaces of methanol, ethanol, 1-heptanol and 1-decanol

Abstract A new apparatus is described for maintaining either a flowing or a stationary liquid surface within an evacuated compartment for the purposes of electron spectroscopy, mass spectroscopy, etc. The liquid is made to flow down a tungsten rod which can be cooled or heated by a saturated slush bath or liquid. The position of the rod is variable so that the liquid surface can be held in the best position and orientation. By varying the rate of flow or by completely stopping the flow of liquid it is possible to examine surfaces at different times after formation and to carry out kinetic studies. The He(I) photoelectron spectra are reported of flowing surfaces of methanol and ethanol at −78°C and also of the vapours above the flow. Spectra of 1-heptanol at 0°C and 1-decanol at 20°C are also given. Contamination of these liquid surfaces with loss of spectral structure occurs in the spectrometer within 30 s to 2 min of formation.

The He(I) photoelectron spectrum of benzyl alcohol-liquid surface and gas phase

Abstract He(I) photoelectron spectra of benzyl alcohol (liquid surface and gas phase) are presented and a simple method is given for the removal of the effects of He(Iβ) impurity. In addition to the general shift to lower ionisation energy usually observed in the spectrum of neutral (uncharged, as opposed to ionic) substances on change of phase from gas to liquid, there are also shifts in the ionisation energies of some bands relative to others: specifically the non-bonding O band shifts on liquefaction by O.5 eV more than the other bands. This relative shift is attributed to hydrogen bonding.

He(I) photoelectron studies of liquids and gases

Abstract He(I)photoelectron spectra of tetramethyl- p -phenylenediamine, phenol, benzyl alcohol and formamide in gaseous and liquid forms have been measured. The structure underlying these spectra is enhanced by plotting them in the form of their second derivatives. Comparison of the spectra of the gas phase and liquid surface reveals the effects of intermolecular interaction and sometimes enables the determination of the molecular form of the surface layer.

Surface activity of solutes in hydroxypropionitrile studied by He(I) photoelectron spectroscopy - EGG lecithin, sodium oleate, malachite green and tris-(dioxa-3,6-heptyl)amine

Abstract We have used He(I) photoelectron spectroscopy to measure the percent surface coverage for substances dissolved in hydroxypropionitrile, HO(CH 2 ) 2 CN. The concentration at which 100% surface coverage is achieved, C 100 , is an inverse measure of surface activity. Measured values of log 10 ( C 100 ), with C 100 in molarity units, in hydroxypropionitrile at 20°C are (in order of diminishing surface activity): −3.85 (egg lecithin), −2.85 (sodium oleate), −0.64 (malachite green hydroxide), and 0.34 [tris(dioxa-3,6-heptyl)amine].

The He(I) photoelectron spectra of lipid phosphatides

Abstract Complete layers of some lipids are formed spontaneously on the surfaces of solutions of sufficient concentration in certain solvents, e.g. phosphatidylcholine (egg lecithin) and phosphatidylinositol (wheat germ) dissolved in hydroxypropionitrile. The He(I) photoelectron spectra of phosphatides in such layers contain: (1) a broad band, assigned to alkyl groups, with maximum intensity at about 11 eV, (2) another broad band at about 8 eV, assigned to the PO - 4 group with about 1 % of the band area of (1).

Auger and electron energy loss studies on liquid surfaces

Abstract The effects of surfactant layers on the Auger and electron energy loss spectra of liquid formamide and hydroxypropionitrile are reported. The characteristic structure of formamide remains in the loss spectrum even when there is complete surface coverage as verified by the Auger spectra.

He(I) photoelectron studies of lipid layers

Abstract It is shown how films of pure or mixed lipids can be investigated by means ofHe(I) photoelectron spectroscopy; the relationship between the results and those from pressure/area studies is discussed. Films of phosphatidylcholine (egg lecithin), cholesterol and mixtures of the two have been studied; a monolayer of lecithin facilitates the early stages of the surface adsorption of cholesterol but a monolayer of cholesterol has the reverse effect on lecithin.

The He(I) photoelectron spectra of aqueous solutions of calcium salts

Abstract The He(I) photoelectron spectra of the surfaces of liquid aqueous solutions of calcium chloride, bromide, iodide and nitrate at −10 to 15°C are reported. Values of vertical ionisation energies (eV±0.3) are: water (lone pair) = 11.2, Cl−(2P) = 10.0, Br−(2P) = 9.0, I−(2P 3 2 ) = 7.8, I−(2P 1 2 ) = 8.6, NO−3 = 10 (shoulder).

The surface activity of p-aminotriphenylmethane dyes in organic solvents - He(I) photoelectron spectra

Abstract At 0.23 M, the superficial layer of a solution of malachite green hydroxide or of brilliant green hydroxide in hydroxy-propionitrile consists entirely of the dye (as measured by He (I) photoelectron spectroscopy). This surface activity is weak or non-existent in the chloride and oxalate of malachite green, in some related dyes like brilliant green bisulphate and in the hydroxides and salts of both p-rosaniline and crystal violet.

Electrostatic charges on surfaces of insulating liquids effects in He(I) photoelectron spectroscopy

Abstract Phenomena and techniques connected with the measurement of the He (I) photoelectron spectra of static and flowing surfaces of insulating liquids are discussed. The electrostatic charges induced by friction are easily detectable by their effect on the photoelectron spectrum; these charges can often be removed by dissolving in the liquid a current carrier such as a tetra-N-butylammonium salt, by flowing gases such as N2 and argon over the surface, or by irradiation with light from a mercury lamp.