File:Collisions of slow moving electrons with nitrogen molecules (1918) (14757124136).jpg

Identifier: collisionsofslow00karr (find matches)
Title: Collisions of slow moving electrons with nitrogen molecules
Year: 1918 (1910s)
Authors: Karrer, Sebastian
Subjects: Electron-molecule collisions Collisions (Physics) Atom-molecule collisions Theses
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Contributing Library: University of Illinois Urbana-Champaign
Digitizing Sponsor: University of Illinois Urbana-Champaign

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nt was further te3ted by varying the accelerating and retardingpotentials in such a way as to keep their difference constant. Thedata tabulated in Fig.3 shows that N is indeed independent of theinitial velocity of the electrons if this velocity is below theionization velocity. 0 Accelerating Retarding Potential Potential N Difference Difference 3 volts 2 volts 6.05 4 3 6.02 5 4 6. 10 6 5 6. 40 7 6 6. 30Fig. 3 Curve No.15 was obtained by graphical differentiation of curve No,16.The derivative is then plotted against the velocity of the electrons.The total area under this curve is proportional to the total cur-rent. The percent of the current carried by electrons having velo-cities between two limits is then obtained by.dividing the area ofthis strip under the curve by the total area under the curve. Theseratios are plotted against the velocity in Gurve No.15. This is theusual method for obtaining velocity-distribution curves. D. Relation Between N and the Retarding Potential Difference
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30 Pet we an A and B. - In general, N increases 9.3 the retardirw ?. D. in-creases, If the accelerating P. D. is kept constant. This relationis shown by Curve No.17 for which the accelerating P.D. was 3 volts.Similar results were obtained for several other values of the poten-tial differences. However, the significance of these results mustbe further investigated. V SUMMARYThe results of this investigation are: 1. An apparatus has been developed in which the collisionsof electronsWith nitrogen molecules can be studied under control-lable conditions of pressure. An equipotential source of electronsis used. 2. It has been experimentally demonstrated that for slowmoving- electrons the equation log;i = - <X (da-d2) gives the relation between the currents and distance, when an elec-trode is moved in nitrogen containing argon as an impurity. 3. The number of electron collisions per centimeter distancevaries directly as the pressure of the gas. 4. The number of electron collisions per cen

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