@article {2186, title = {Darling-Dennison resonance and Coriolis coupling in the bending overtones of the (A)over-tilde (1)A(u) state of acetylene, C2H2}, journal = {Journal of Chemical Physics}, volume = {129}, number = {5}, year = {2008}, note = {ISI Document Delivery No.: 336AGTimes Cited: 3Cited Reference Count: 57Merer, Anthony J. Yamakita, Nami Tsuchiya, Soji Steeves, Adam H. Bechtel, Hans A. Field, Robert W.}, month = {Aug}, pages = {19}, type = {Article}, abstract = {Rotational analyses have been carried out for the overtones of the nu(4) (torsion) and nu(6) (in-plane cis-bend) vibrations of the (A) over tilde (1)A(u) state of C2H2. The v(4)+v(6)=2 vibrational polyad was observed in high-sensitivity one-photon laser-induced fluorescence spectra and the v(4)+v(6)=3 polyad was observed in IR-UV double resonance spectra via the ground state nu(3) (Sigma(+)(u)) and nu(3)+nu(4) (Pi(u)) vibrational levels. The structures of these polyads are dominated by the effects of vibrational angular momentum: Vibrational levels of different symmetry interact via strong a-and b-axis Coriolis coupling, while levels of the same symmetry interact via Darling-Dennison resonance, where the interaction parameter has the exceptionally large value K-4466=-51.68 cm(-1). The K-structures of the polyads bear almost no resemblance to the normal asymmetric top patterns, and many local avoided crossings occur between close-lying levels with nominal K-values differing by one or more units. Least squares analysis shows that the coupling parameters change only slightly with vibrational excitation, which has allowed successful predictions of the structures of the higher polyads: A number of weak bands from the v(4)+v(6)=4 and 5 polyads have been identified unambiguously. The state discovered by Scherer [J. Chem. Phys. 85, 6315 (1986)], which appears to interact with the K=1 levels of the 3(3) vibrational state at low J, is identified as the second highest of the five K=1 members of the v(4)+v(6)=4 polyad. After allowing for the Darling-Dennison resonance, the zero-order bending structure can be represented by omega(4)=764.71, omega(6)=772.50, x(44)=0.19, x(66)=-4.23, and x(46)=11.39 cm(-1). The parameters x(46) and K-4466 are both sums of contributions from the vibrational angular momentum and from the anharmonic force field. For x(46) these contributions are 14.12 and -2.73 cm(-1), respectively, while the corresponding values for K-4466 are -28.24 and -23.44 cm(-1). It is remarkable how severely the coupling of nu(4) and nu(6) distorts the overtone polyads, and also how in this case the effects of vibrational angular momentum outweigh those of anharmonicity in causing the distortion. (C) 2008 American Institute of Physics.}, keywords = {ANHARMONIC-OSCILLATOR MODEL, DISPERSED, ELECTRONIC-TRANSITION, EXCITED-STATES, FLUORESCENCE-SPECTRUM, INTRAMOLECULAR VIBRATIONAL REDISTRIBUTION, PARTIAL DEPERTURBATION, POLYATOMIC-MOLECULES, ROTATION CONSTANTS, TRIPLET PERTURBATIONS, X BAND SYSTEM}, isbn = {0021-9606}, url = {://000258336100016}, author = {Merer, A. J. and Yamakita, N. and Tsuchiya, S. and Steeves, A. H. and Bechtel, H. A. and Field, R. W.} } @article {2046, title = {Density functional theory calculation of 2p spectra of SiH4, PH3, H2S, HCl, and Ar}, journal = {International Journal of Quantum Chemistry}, volume = {108}, number = {8}, year = {2008}, note = {ISI Document Delivery No.: 297FSTimes Cited: 0Cited Reference Count: 48Chong, Delano P. Segala, Maximiliano Takahata, Yuji Baerends, E. J.}, month = {Jul}, pages = {1358-1368}, type = {Article}, abstract = {The method developed recently for prediction of Is electron spectra is now extended to the 2p spectra of SiH4, PH3, H2S, HCl, and Ar. The method for X-ray absorption spectra involves the use of Delta E for the excitation and ionization energies, and application of time-dependent density functional theory using the exchange-correlation potential known as statistical average of orbital potentials for the intensities. Additional assumptions and approximations are also made. The best exchange-correlation functional E-xc for the earlier calculation of Delta E in Is spectra of C to Ne (namely Perdew-Wang 1986 exchange, combined with Perdew-Wang 1991 correlation) is no longer used in this work on 2p spectra of Si to Ar. Instead, recently tested Exc good for 2p core-electron binding energies (known as OPTX) for exchange and LYP for correlation, plus scalar zeroth-order regular approximation is adopted here for the Delta E calculations. Our calculated X-ray absorption spectra are generally in good agreement with experiment. Although the predictions for the higher excitations suffer from basis set difficulties, our procedure should be helpful in the interpretation of absorption spectra of 2p electrons of Si to Ar. In addition, we report calculated results for other kinds of electron spectra for SiH4, PH3, H2S, HCl, and Ar, including valence electron ionizations and excitations as well as X-ray emission. (C) 2008 Wiley Periodicals, Inc.}, keywords = {2p spectra, ACCURATE, CORE, DFT, ELECTRON BINDING-ENERGIES, EXCHANGE-CORRELATION POTENTIALS, EXCITATION-ENERGIES, excitations, EXCITED-STATES, GAS, INNER, ionizations, MOLECULES, PHOTOELECTRON-SPECTRA, X-ray absorption spectra, X-ray emission spectra}, isbn = {0020-7608}, url = {://000255603100007}, author = {Chong, D. P. and Segala, M. and Takahata, Y. and Baerends, E. J.} } @article {1082, title = {Density functional calculation of K-shell spectra of small molecules}, journal = {Journal of Electron Spectroscopy and Related Phenomena}, volume = {148}, number = {2}, year = {2005}, note = {ISI Document Delivery No.: 945UITimes Cited: 10Cited Reference Count: 44}, month = {Aug}, pages = {115-121}, type = {Article}, abstract = {Both Delta E-KS and time-dependent density functional theory (TD-DFT) methods, with approximations for the singlet-triplet splitting and for the relativistic corrections, were tested for the calculation of K-shell spectra of Ne, HF, H2O, NH3, CH4, and CO. Results from several exchange-correlation functionals as well as diffuse basis sets were compared with available experimental data. Excellent core excitation and core-electron ionization energies for Ne, HF, H2O, NH3, CH4, and CO can be obtained from Delta E with Perdew-Wang 1986 exchange and Perdew-Wang 1991 correlation functionals; and reasonable intensities for singlet excitations, from TD-DFT with exchange-correlation potential known as statistical average of orbital potentials. The dependence of the quality of Delta E on basis set is as expected: excitations to higher Rydberg levels requiring more diffuse functions. However, the oscillator strength seems to be more sensitive to the quality of the basis set. Suggestions are made for extending the procedure to larger systems. (c) 2005 Elsevier B.V. All rights reserved.}, keywords = {ACCURATE, CO, core-electron binding energies, DFT, diffuse STO functions, EDGE, ELECTRON BINDING-ENERGIES, EXCITATION, EXCITED-STATES, GAS-PHASE, inner-shell excitation spectra, intensities, NEON, OSCILLATOR-STRENGTHS, relative, Rydberg levels, Slater-type orbitals, SPECTROSCOPY, time-dependent DFT}, isbn = {0368-2048}, url = {://000230527300007}, author = {Chong, D. P.} } @article {904, title = {"Spectrum-only" assignment of core-penetrating and core-nonpenetrating Rydberg states of calcium monofluoride}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {82}, number = {6}, year = {2004}, note = {ISI Document Delivery No.: 861XATimes Cited: 3Cited Reference Count: 38}, month = {Jun}, pages = {791-803}, type = {Article}, abstract = {Rydberg states of calcium monofluoride in the n* = 17-20 region have been observed by ionization-detected optical-optical double-resonance spectroscopy via the D(2)Sigma(+) v = 1 intermediate state. All members of the six core-penetrating Rydberg series in the n* = 17-20 region and several components of the 17f and 17g core-nonpenetrating Rydberg states have been assigned. While the assignment of core-penetrating Rydberg states is straightforward without use of an effective Hamiltonian model, "spectrum-only" assignment of core-nonpenetrating states is complicated because strong l-uncoupling causes the core-nonpenetrating states to evolve rapidly from Hund{\textquoteright}s case (b) to Hund{\textquoteright}s case (d) coupling. We describe "spectrum-only" assignment procedures, developed in the spirit of Gerhard Herzberg, that can be used to assign optical-optical double-resonance spectra of core-penetrating and core-nonpenetrating Rydberg states using only information contained in the spectrum rather than predictions derived from an effective Hamiltonian model. The ambiguities that arise in the assignment of each class of states are discussed in detail.}, keywords = {ANGULAR-MOMENTUM STATES, AUTOIONIZATION, CaF, DECAY DYNAMICS, electric quadrupole moment, EXCITED-STATES, HIGHER, IONIZATION, laser spectroscopy, MAGNETIC-FIELD, NO, QUANTUM-DEFECT THEORY, Rydberg states, TRIPLE-RESONANCE SPECTROSCOPY}, isbn = {0008-4042}, url = {://000224450700014}, author = {Kay, J. J. and Byun, D. S. and Clevenger, J. O. and Jiang, X. and Petrovi, V. S. and Seiler, R. and Barchi, J. R. and Merer, A. J. and Field, R. W.} } @article {410, title = {The electronic spectrum of NiCN in the visible region}, journal = {Journal of Molecular Spectroscopy}, volume = {215}, number = {1}, year = {2002}, note = {ISI Document Delivery No.: 601LETimes Cited: 18Cited Reference Count: 74}, month = {Sep}, pages = {106-127}, type = {Article}, abstract = {The electronic spectrum of NiCN in the 500-630 nm region has been observed by laser-induced fluorescence, following the reaction of laser-ablated nickel atoms with cyanogen under free jet expansion conditions. Seven electronic states hake been identified. Three of these, (X) over tilde (1) (2)Delta(5/2), (X) over tilde (2) (2)Delta(3/2), and (W) over tilde (2)(1)Pi(3/2), are derived from the electron configuration Ni+ (3d(8) 4s) CN, and the other four, (A) over tilde (2) Delta(5/2), (B) over tilde (2)Pi(3/2), (C) over tilde (2)Phi(7/2) and (D) over tilde (2)Phi(5/2), are derived from the configuration Ni+ (3d(8) 4s) CN. Rotational analysis of bands of (NiCN)-N-14 and (NiCN)-N-15 at high resolution has given the bond lengths in the (X) over tilde (2)(1)Delta(5/2) ground state as r(0) (Ni-C) = 1.8292 +/- 0.0028 Angstrom; r(0) (C-N) = 1.1591 +/- 0.0029 Angstrom. The orbital angular momentum splits the bending fundamental of the (X) over tilde (2)(1)Delta(5/2) state into two vibronic components, which lie at 243.640 cm(-1) ((2)Pi(3/2)) and 244.964 cm(-1) ((2)Phi(7/2)). Exceptionally strong Fermi resonance occurs in the ground state between the Ni-C stretching vibration, nu(3), and the overtone of the bending vibration. Sixty vibrational levels of the ground state with /l/ = 0 and l have been assigned, They could tie fitted by least squares to a simple matrix representation of the Fermi resonance that ignores the orbital angular momentum the interaction matrix element, as a fraction of the bending frequency, turns out to be larger than that in the "prototype" molecule, CO2. The two low-lying excited electronic states, (X) over tilde (2)Delta(3/2) at 830 cm(-1) and (W) over tilde (2)(1)Pi(3/2) at 2238 cm(-1), have very similar properties to the ground state. The energies of the excited states in the visible region bear a remarkable resemblance to those found in NiH (S, A. Kadavathu et al., 1991, J. Mol. Spectrosc. 147, 448-470). Again, the effects of Fermi resonance in them are large but those of vibronic coupling are surprisingly small. The most significant vibronic coupling occurs between the (A) over tilde (2)Delta(5/2) and (B) over tilde (2)Pi(3/2) states, which are separated by 79 cm(-1), an interval which is less than half the frequency of the bending vibration that couples them large numbers of vibronically induced bands appear in the excitation and dispersed emission spectra, but the splitting between (tie vibronic components of the bending fundamental of the (A) over tilde (2)Delta(5/2) state is only 6.988 cm(-1). Rotational perturbations are widespread in the (A) over tilde (2)Delta(5/2) state, particularly in the levels of the nu(3) (Ni-C stretching) progression, Vibrational assignments have been made on the basis of the Ni-58-Ni-60 isotope shifts at high resolution and the Franck-Condon patterns in dispersed emission spectra, Various weak unassigned bands, both in the excitation and the dispersed emission spectra, give evidence for the existence of at least three more excited electronic states which it has not been possible to characterize in detail. (C) 2002 Elsevier Science (USA)}, keywords = {ANION PHOTOELECTRON-SPECTROSCOPY, EXCITED-STATES, FOURIER-TRANSFORM SPECTROSCOPY, LASER-INDUCED FLUORESCENCE, LITHIUM ISOCYANIDE, LOW-LYING STATES, MG-BEARING, MICROWAVE, MOLECULE, POTENTIAL-ENERGY SURFACE, ROTATIONAL SPECTRUM, SPECTROSCOPY}, isbn = {0022-2852}, url = {://000178446800011}, author = {Kingston, C. T. and Merer, A. J. and Varberg, T. D.} } @article {3572, title = {ROTATIONAL SPECTRA OF THE MIXED RARE-GAS DIMERS NE-KR AND AR-KR}, journal = {Journal of Chemical Physics}, volume = {103}, number = {8}, year = {1995}, note = {ISI Document Delivery No.: RP715Times Cited: 29Cited Reference Count: 40}, month = {Aug}, pages = {2827-2833}, type = {Article}, abstract = {Pure rotational spectra of several isotopomeric species of the rare gas dimers Ne-Kr and Ar-Kr have been measured using a pulsed jet cavity microwave Fourier transform spectrometer. Equilibrium internuclear distances have been evaluated by taking advantage of the isotopic data, for both these dimers and three Xe-containing dimers, whose spectra were reported earlier [Jager et al., J. Chem. Phys. 99, 919(1993)]. The dipole moments have been estimated using the {\textquoteright}{\textquoteright}pi/2-pulse{\textquoteright}{\textquoteright} excitation condition. Kr-83 nuclear quadrupole hyperfine structure has been observed in some rotational transitions of Ne-20-Kr-83 and of Ar-Kr-83, and the corresponding quadrupole coupling constants have been derived. (C) 1995 American Institute of Physics.}, keywords = {CONSTANTS, DEPENDENCE, DIATOMIC-MOLECULES, DUNHAM COEFFICIENTS, EXCITED-STATES, FABRY-PEROT CAVITY, ISOTOPE, POTENTIALS, TRANSFORM MICROWAVE SPECTROSCOPY, ULTRAVIOLET-LASER SPECTROSCOPY, XE}, isbn = {0021-9606}, url = {://A1995RP71500006}, author = {Xu, Y. J. and Jager, W. and Djauhari, J. and Gerry, M. C. L.} } @article {2960, title = {FIRST SPECTROSCOPIC EVIDENCE FOR A MUONIUM-CONTAINING MOLECULE - NEMU-ASTERISK CHEMILUMINESCENCE}, journal = {Journal of Chemical Physics}, volume = {101}, number = {2}, year = {1994}, note = {ISI Document Delivery No.: NW979Times Cited: 4Cited Reference Count: 102}, month = {Jul}, pages = {1202-1218}, type = {Review}, abstract = {Evidence for the formation of NeMu*, an isotopic analog of the Rydberg molecule NeH*, has been obtained from the observation of chemiluminescent emission in the near-infrared region. This is the first spectroscopic detection of a muonium-containing molecule. NeMu* was formed by stopping a 4 MeV muon (mu(+)) beam in a target vessel containing 1-6 atm of Ne and. similar to 1 Torr Ar. The wavelength spectrum of the emission, from similar to 680-1000 nm, was measured, using a variable-wavelength filter, with a resolution of +/-12.5 nm. Lower resolution spectra were also taken with a series of long pass filters. A complete histogram of photon events vs time was collected for each wavelength. Two strong transitions are observed, centered at 818 and 943 nm. Identification of NeMu* was made by a comparison of the experimental spectrum with a simulated spectrum based on detailed ad initio calculations, extended to higher excitation levels than had heretofore been reported. Both experimental and theoretical results are reported here. Although the mechanism by which the emitting states in NeMu* are formed remains unclear, radiolysis effects appear to play a dominant role, indicating that NeMu(+) (the product of muon thermalization in Ne) undergoes charge exchange with metastable Ar* and/or is neutralized by a spur electron, both species produced during the slowing down of the high energy muon.}, keywords = {2-SIGMA-2-SIGMA TRANSITIONS, CHARGE-EXCHANGE COLLISIONS, COMPETING PROCESSES, DISSOCIATION, EMISSION-SPECTRA, EXCITED-STATES, GAUSSIAN-BASIS SETS, radiative, RARE-GAS HYDRIDES, REACTION-KINETICS, Rydberg states}, isbn = {0021-9606}, url = {://A1994NW97900034}, author = {Baer, S. and Fleming, Donald G. and Sloan, J. J. and Arseneau, D. J. and Kolbuszewski, M. and Wright, J. and Senba, M. and Pan, J. J. and Snooks, R.} } @article {2834, title = {PURE ROTATIONAL SPECTRA OF THE MIXED RARE-GAS VAN-DER-WAALS COMPLEXES NE-XE, AR-XE, AND KR-XE}, journal = {Journal of Chemical Physics}, volume = {99}, number = {2}, year = {1993}, note = {ISI Document Delivery No.: LM894Times Cited: 48Cited Reference Count: 50}, month = {Jul}, pages = {919-927}, type = {Article}, abstract = {Pure rotational transitions in the vibrational ground states of various isotopomers of the heteronuclear rare gas dimers Ne-Xe, Ar-Xe, and Kr-Xe have been measured using a pulsed molecular beam cavity microwave Fourier transform spectrometer. Rotational and centrifugal distortion constants have been obtained, and have yielded estimates of the lengths of the van der Waals bonds and of their harmonic vibration frequencies. Effects due to nuclear quadrupole coupling have been observed in Xe-131-containing complexes and have yielded the corresponding nuclear quadrupole coupling constants. The electric molecular dipole moments of the complexes have been estimated from the excitation pulse lengths, optimized for maximum signal strength (pi/2 condition).}, keywords = {ARGON, CONSTANTS, curve, DIPOLE-MOMENTS, EXCITED-STATES, INTERATOMIC POTENTIALS, PAIRS, SPECTROMETER, TRANSFORM MICROWAVE SPECTROSCOPY, ULTRAVIOLET-LASER SPECTROSCOPY}, isbn = {0021-9606}, url = {://A1993LM89400017}, author = {Jager, W. and Xu, Y. J. and Gerry, M. C. L.} }