摘要:

A method (the New Vector Model : NVM) designed to approach the intensity of the secondary transition of the benzene chromophore with-CH3 and-OR substituents, has been recently published1This method is based on MNDO calculations. It has been applied to strained chromophores with fused rings,2assuming that it is possible to take into account the incidence of strain on intensity in introducing a strain vector in the vector scheme used to calculate the transition moment vector. In another step it has been derived a much simpler method which avoids the quantum calculations. It can be brought into play using graphically simple vector addition rules.3This method is based on a new concept : the interaction vector (underneath, the method is called the Interaction Vector Model : IVM). It has been designed to study alkyl and-OR substituents, since we are mainly involved in the study of natural products and many natural products display such substituents. This IVM has not been designed to take into account the perturbations induced by the strain on intensity. The present work is devoted to the adaptation of the IVM to strained benzene chromophores. It is given several examples on the way it can be used on strained natural molecules.

ISSN:0038-7010    

DOI:10.1080/00387019408000865

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The present study was conducted to investigate the molecular absorption of sulfur dioxide in a carbon rod furnace for the determination of sulfur. The arsenic atomic line at 206.98 nm emitted from an As-hollow cathode lamp was used as an irradiation source in the measurements. The interferences caused by molecular absorption of some other molecules present in these conditions was also examined. Using the ionexchange as the pretreatment for the sample the method can be applied for a great variety of inorganic samples.

ISSN:0038-7010    

DOI:10.1080/00387019408000866

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor