Pressure dependence of zero‐field splittings in organic triplets. III. Vibronic systems

1992 ◽  
Vol 96 (8) ◽  
pp. 5591-5599 ◽  
Author(s):  
J. L. Baber ◽  
I. Y. Chan
Keyword(s):  
Pressure Dependence ◽  
Zero Field

scholarly journals Pressure Dependence and End Effects in Precision Ion Mobility Studies

1974 ◽  
Vol 27 (2) ◽  
pp. 211 ◽  
Author(s):  
MT Elford ◽  
HB Milloy
Keyword(s):  
Pressure Dependence ◽  
Zero Field ◽  
Surface Layers ◽  
End Effects ◽  
Pressure Limit ◽  
Fitting Procedure ◽  
Resonant States ◽  
Mobility Studies ◽  
Cluster Ion ◽  
Reduced Mobility

The mobilities of K + ions have been measured by the Bradbury-Nielsen method in He, Ar, H2 and N 2 at 293 K at pressures and E/Nvalues in the range 1�4-190 torr and 1-28 Td respectively. Three drift tubes were used with drift lengths of 3� 395, 9� 076 and 50�00 cm. The anomalous variation of the reduced mobility with E/ N at low values of E/ N reported by Elford (1971) has been shown to be due to the presence of charged surface layers on the first grid of the time-of-flight system. The dependence of the reduced mobility on pressure also reported by Elford has been confirmed, and an explanation of the pressure dependence in He, Ar and H2 is proposed in terms of the formation of ion-atom or ionmolecule complexes in orbiting resonant states. The zero-field reduced mobilities in the zero-pressure limit have been derived by a fitting procedure and found to be 21 �3 � O' 2, 2�64 � O� 02 and 12� 8 � O' 1 cm2 y-1 S-l for He, Ar and H2 respectively. The pressure dependence of the reduced mobility for K + ions in N2 is shown to be of a different form from the other gases investigated and to be due to the formation of the cluster ion K + . N2. The present data are consistent with the equilibrium constant of Beyer and Keller (1971) for the reaction K + + N2 + N2 +� K + . N2 + N2. The zero-field reduced mobility for K+ ions in N2 in the zero-pressure limit has been found to be 2�50�0�02 cm2 Y-1 s-1.

scholarly journals Quantum Phenomena and the Mobility of Potassium Ions in Argon

1974 ◽  
Vol 27 (2) ◽  
pp. 227 ◽  
Author(s):  
RO Watts
Keyword(s):  
Alkali Metal ◽  
Pressure Dependence ◽  
Room Temperature ◽  
Quantum Mechanical ◽  
Alkali Metal Ions ◽  
Potassium Ions ◽  
Zero Field ◽  
Mechanical Methods ◽  
Quantum Phenomena ◽  
Reduced Mobility

Recent work on the mobilities of alkali metal ions in the noble gases has indicated that there is a pressure dependence of the zero-field reduced mobility. The possibility of temporarily bound dimmers being responsible for this pressure dependence is examined here by quantum mechanical methods for the case of potassium ions in argon and it is shown that the conditions needed for a small pressure dependence do exist at room temperature.

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