MEASUREMENT OF STATIC POLARIZABILITIES ON C10H8 AND C10D8

Laser Stark spectroscopy has been performed on C10H8 and C10D8 molecules in a collimated, seeded supersonic beam. The Stark splittings and shifts of many rotational lines in the 8(0)1 band of the A 1B3u <-- X 1A(g) transition of naphthalene-H8 and -D8 could be measured in a static homogeneous electric field. The determined polarizability anisotropies of the A 1B3u state of C10H8 are P'aa - P'bb = 9.9(2) angstrom 3 and P'bb - P'cc = 6.4(2) angstrom 3, whereas the X 1A(g) ground state results are P"aa - P"bb = 6.2(2) angstrom 3 and P"bb - P"cc = 7.2(2) angstrom 3. The change of the average polarizability between these states was determined to DELTA-P = P' - P" = 1.6(1) angstrom 3. The corresponding values of C10D8 were found to be P'aa - P'bb = 10.1(2) angstrom 3, P'bb - P'cc = 6.2(2) angstrom 3, P"aa - P"bb = 6.1(2) angstrom 3, P"bb - P"cc = 7.3(2) angstrom 3 and DELTA-P = P' - P" = 1.6(1) angstrom 3.