High-resolution broad-scan gas-phase photoelectron spectra using synchrotron radiation (including valence, inner valence, and core levels) are: reported for a series of trimethylphosphine-substituted tungsten carbonyls: W(CO)(6), W(CO)(5)PMe3, cis-W(CO)(4)(PMe3)(2), trans-W(CO)(4)(PMe3)(2), and fac-W(CO)(3)(PMe3)(3). The inner valence and core level spectra are interpreted by comparison with the published spectra of W(CO)(6) and other metal carbonyls. High-resolution valence level spectra of these complexes are also obtained by He I radiation. Fine structure, resulting from spin-orbit splitting, ligand field splittings, and vibrational coupling is resolved in the spectra of both W 5d and W 4f regions. Ligand field splittings on both the W 5d and W 4f levels increase in the order W(CO)(6) approximate to fac-W(CO)(3)(PMe3)(3) < W(CO)(5)PMe3 less than or equal to cis-W(CO)(4)(PMe3)(2) < trans-W(CO)(4)(PMe3)(2). For the first time, the phosphorus 2p spin-orbit components of the phosphine complexes have been resolved. The binding energies (or ionization potentials) in the spectra of both W 5d valence level and W 4f core level regions are shifted almost linearly to lower energy with each successive step of ligand substitution. The shift per phosphine substitution is 0.66 +/- 0.03 eV for the W 5d ionizations and 0.76 +/- 0.03 eV for the W 4f ionizations (Delta E-valence/ Delta E-core = 0.86 +/- 0.03). Similar linear shift trends are also found in the phosphorus 2p core level and phosphorus valence "'lone-pair" ionizations. These data confirm the ligand additivity model predictions for these complexes.