Determination of the structure of ArHCl

摘要

The radio frequency and microwave spectra ofKequals; 0 states of ArHCl and ArDCl have been measured by molecular beam electric resonance spectroscopy. The rotational and hyperfine structure constants for the lowest vibrational state of the four isotopic species areArH35thinsp;ClArD35thinsp;ClBmacr; equals; lpar;Bplus;Crpar;sol;2 equals; 1.678511 lpar;5rpar;GHzBmacr; minus; 2DJequals; 1.657596 lpar;10rpar;GHzDJequals;20.33 lpar;20rpar;kHzlpar;eqQrpar;aC1equals; minus;36.250 lpar;20rpar;MHzlpar;eqQrpar;aequals;minus;23.027lpar;10rpar;MHzlpar;eqQrpar;aDequals; plus;102.3 lpar;50rpar;kHzmgr;aequals;0.81144lpar;10rpar;Dmgr;aequals;1.00355lpar;70rpar;DArH37thinsp;ClArD37thinsp;ClBmacr; minus; 2DJequals; 1.631566 lpar;5rpar;GHzBmacr; minus; 2DJequals; 1.611876 lpar;10rpar;GHzOnly the lowest vibrational state has been observed. The molecule is extremely nonrigid. The average Arsngbnd;Cl distance is 4.006 Aring; in ArHCl and 4.025 Aring; in ArDCl. The Arsngbnd;Clsngbnd;H angle is acute and the amplitude of the zero point angle bending is extremely large. The average Arsngbnd;Clsngbnd;H angle is near 45deg;, while the average Arsngbnd;Clsngbnd;D angle is near 34deg;. The vibrational frequency of Arsngbnd;HCl bond stretching is computed to be 32.2 cmminus;1from the observed centrifugal distortion constant.