Microwave Spectrum of Dimethylgermane

摘要

The rotational spectrum of the five Ge isotopic species of dimethylgermane has been investigated in the region 8ndash;35 GHz. All identified transitions were split into quartets by the internal rotation of the methyl groups. From the splittings a barrierV3thinsp;equals;thinsp;1182calsol;molehas been determined. Rotational constants for theA1A1ground torsional state of the74Ge species areAthinsp;equals;thinsp;12 522.67MHz, Bthinsp;equals;thinsp;5587.68MHz, andCthinsp;equals;thinsp;4264.57MHz. No hyperfine structure due to the quadrupole moment of73Ge was resolved giving upper limitsverbar;thinsp;khgr;aathinsp;verbar;thinsp;thinsp;3.0MHz, verbar;thinsp;khgr;bbthinsp;verbar;thinsp;thinsp;3.6MHz. Starkhyphen;effect measurements gave a dipole moment of 0.616 D. With assumption of the methylhyphen;group dimensions, structural parameters for the heavy atoms were calculated to be:rCHthinsp;equals;thinsp;1.083 Aring;(assumed),ang;HCHthinsp;equals;thinsp;108.5deg;(assumed),rCGethinsp;equals;thinsp;1.950thinsp;plusmn;thinsp;0.003 Aring;, ang;CGeCthinsp;equals;thinsp;110.0thinsp;plusmn;thinsp;0.5deg;. No tilt of the methyl groups was detected.