Computational study of negative ions influence on plasma sheath formation

3-substituted beta-carbolines of the formula wherein RC is hydrogen, lower alkyl, alkoxyalkyl of up to 6 C-atoms, cycloalkyl of 3-6 C-atoms, aralkyl of up to 8 C-atoms, or (CH2)nOR20 wherein R20 is alkyl of up to 6 C-atoms, cycloalkyl of 3-6 C-atoms or aralkyl of up to 8 C-atoms and n is an integer of 1 to 3; Y is oxygen, two hydrogen atoms or NOR1, wherein R1 is hydrogen, lower alkyl, aryl or aralkyl of up to 6 C-atoms, COR2, wherein R2 is lower alkyl of up to 6 C-atoms, or Y is CHCOOR3, wherein R3 is hydrogen or lower alkyl or Y is NNR4R5, wherein R4 and R5 can be the same or different and each is hydrogen, lower alkyl, C6-10-aryl, C7-10-aralkyl or CONR6R7, wherein R6 and R7 can be the same or different and each is hydrogen or lower alkyl or R4 and R5 together with the connecting N-atom, for a 5- or 6-membered heterocyclic ring which optionally may also contain an O-atom or up to 3 N-atoms and which optionally may be substituted by a lower alkyl group; Z is hydrogen, or alkoxy or aralkoxy each of up to 10 C-atoms and each optionally substituted by hydroxy, or Z is alkyl of up to 6 C-atoms, C6-10-aryl or C7-10-aralkyl each of which may optionally be substituted by a COOR8- or a CONR9R10 group, wherein R8 is alkyl of up to 6 C-atoms, and R9 and R10 can be the same or different and each is hydrogen or alkyl of up to 6 C-atoms; or Z is NR9R10, wherein R9 and R10 are as defined above; or Z is NR11CHR12R13, wherein R11 and R12 each is hydrogen or together form a N=C double bond, wherein R13 is C1-10-alkyl or NR14R15, wherein R14 and R15 are the same or different and each is hydrogen, OH or alkyl or alkoxy each of up to 6 C-atoms, or wherein R12 and R13 together are oxygen, in which case, R11 is hydrogen; or Z is COOR2 wherein R2 is as defined above; or Y and Z, together with the connecting C-atom, may form a 5- or 6-membered heterocyclic ring which contains an O-atom, adjoining O- and N-atoms or up to 4 N atoms and which optionally may be substituted by a lower alkyl group, hydroxy or oxo have valuable psychotropic properties which make them useful for example as tranquilizers.