摘要 : We report a reinvestigation of the 6snf1,3F3 (9 less than or equal n less than or equal 30), 6snp1P1 (12 less than or equal n less than or equal 56), 6snp3P1 (12 less than or equal n less than or equal 21) and 6snp3P2 (12 less tha... 展开 We report a reinvestigation of the 6snf1,3F3 (9 less than or equal n less than or equal 30), 6snp1P1 (12 less than or equal n less than or equal 56), 6snp3P1 (12 less than or equal n less than or equal 21) and 6snp3P2 (12 less than or equal n less than or equal 19) Rydberg states of ytterbium atom using a two-colour three-photon resonant excitation technique through the 4f146s5d1D2 intermediate level. The spectra were observed using two dye lasers simultaneously pumped by a common Nd:YAG laser in conjunction with a thermionic diode ion detector. Some new levels have been identified in the vicinity of the 6snf(9 less than or equal n less than or equal 16) Rydberg levels. Three new perturbers 4f135d26s3D3 at 48 584.1 cm-1, 4f135d26s1F3 at 49 122.4 cm-1 and 4f135d26s3G3 at 49 661.6 cm-1 have been located in addition to observation of the 6s9d1D2 and 6p21D2 even parity levels due to sequential excitation from the 6s6p1P1 level. The interchannel interactions among the J = 2 and J = 3 channels have been analyzed using multichannel quantum defect theory. 收起