The rotational spectrum, geometry, and intermolecular force constant of the heterodimer of hydrogen cyanide and fluoroform

摘要

The groundhyphen;state rotational spectra of six isotopic species of an intermolecular complex formed by hydrogen cyanide and fluoroform have been measured using the pulsedhyphen;nozzle, Fourierhyphen;transform microwave technique. The rotational constantB0, the centrifugal distortion constantsDJ,DJK,HJ,HJK, andHKJ, and, where appropriate, the nuclear quadrupole coupling constants khgr;(14N) and khgr;(D) have been determined for each of the species HC14Nsdot;sdot;sdot;HCF3, DC14Nsdot;sdot;sdot;HCF3, HC14sdot;sdot;sdot;DCF3, HC15Nsdot;sdot;sdot;HCF3, HC15Nsdot;sdot;sdot;DCF3, and DC15Nsdot;sdot;sdot;HCF3. For HC14Nsdot;sdot;sdot;HCF3the values are as follows:B0=1151.2991(4) MHz,DJ=1.91(1) kHz,DJK=282.75(6) kHz,HJ=minus;0.1(1) Hz,HJK=44.3(5) Hz,HKJ=53(5) Hz, and khgr;(14N)=3.948(8) MHz. The form of the spectra and magnitudes of the rotational constants allow the conclusion that the geometry of the complex is ofC3Vsymmetry with the nuclei in the order HCNsdot;sdot;sdot;HCF3and lead tor(Nsdot;sdot;sdot;C)=3.489(2) Aring; for HCF3species but 3.483(1) Aring; for DCF3species. The intermolecular stretching force constant determined fromDJisksgr;=3.52 Nthinsp;mminus;1.