Ping Yi Feng

The ionization potentials of Agn and Aun and binding energies of Agn, Aun, Agn+ and Aun+ (n = 1–4)

Abstract The ionization potentials and binding energies of gold and silver clusters and their positive ions containing up to four atoms are investigated using a complete active space MCSCF followed by multi-reference singles + doubles CI which included up to 1.9 million configurations. The ionization potentials for both Au n and Ag n as a function of cluster size n exhibit an interesting “saw-tooth” behavior. The total binding energies of both the clusters and ions as a function of size reveal that the tetramers of gold and silver exhibit unusual stabilities. The gold clusters in general have larger AEs and IPs in comparison to silver clusters due to relativistic effects.

Potential‐energy surfaces for Pt2+H and Pt+H interactions

Potential‐energy surfaces for ten electronic states of Pt2H as a function of Pt2–H distance are constructed using the complete active space multiconfiguration self‐consistent field followed by multireference singles plus doubles configuration interactions which included up to 407 000 configurations. In addition, the spin‐orbit effects were included through the relativistic configuration‐interaction method. The potential‐energy curves of low‐lying electronic states of PtH and spectroscopic constants of 11 states of PtH are also computed using the same method. The experimental A’–X2 spectroscopic bands of PtH are reassigned to the 2Σ+(II)–1/2(I) transition. A tentative reassignment of the observed B’–X1 system is also suggested. The ground state of Pt2H is found to be of E(I) symmetry when spin‐orbit effects are incorporated with a bridged structure [Re(Pt–Pt)=2.46 A, Re(Pt–H)=1.684 A]. A very low‐lying excited state E(II) (Te=0.14 eV) was found for Pt2H. The De(Pt2H)=59 kcal/mol compared to the De(PtH)=72 ...

Electronic states and potential energy surfaces of PdH2: Comparison with PtH2

Complete active space MCSCF (CASSCF) followed by multireference singles and doubles configuration interaction (MRSDCI) calculations are carried out on 13 electronic states of PdH2 and 9 electronic states of PdH+ . The bending potential energy surfaces of 1A1 and 3A1 electronic states were obtained. The 1A1 surface contains two bent minima (θe =30° and θe =62°) and a higher linear minimum separated by a saddle point. The 3A1 surface is relatively flat in the region of the saddle point. The Pd(1S0 ) atom forms a weak complex with H2 but inserts spontaneously into H2 while the Pd(3D3 ) atom has to surmount a large barrier for insertion into H2. The spin–orbit effects for the electronic states of PdH2 are estimated through relativistic configuration interaction calculations of PdH+ whose d Mulliken population is close to that of the d population of PdH2. The ground state of PdH2 is found to be a weakly bound bent 1A1 state with θe =30° and re (Pd–H)=1.67 A. The electronic state and potential energy surfaces o...

Relativistic calculations of electronic states of PdH

Relativistic configuration interaction calculations of five ω–ω states [3/2, 1/2, 1/2(II), 3/2(II), 5/2] of TeH are carried out. Comparison calculations of the 2Π and 4Π λ–s states are also carried out with the objective of understanding the effect of spin–orbit interaction on the electronic states of TeH. These calculations enable assignment of some of the experimentally observed spectra. The 1/2(II), 3/2(II), and 5/2 states exhibit interesting avoided crossings.

Nearly-degenerate electronic states for Ga3P2 and Ga2P3

Nearly-degenerate 2A1 and 2B1(C2y) electronic states are found with distorted trigonal bipyramid and edge-capped tetrahedral geometries together with a E′(D3h) state for Ga3P2, while a distorted structure with 2B1 symmetry and a 2A″2 undistorted D3h structure are found to be nearly-degenerate for Ga2P3. We employ the complete active space multi-configuration self-consistent field followed by multi-reference singles + doubles configuration interaction (MRSDCI) computations that included up to 2.5 million configurations.

Electronic states and potential energy curves of Ga2P, GaP2, and their ions

Abstract Five low-lying electronic states of GaP 2 and GaP 2 + , and seventeen electronic states of Ga 2 P and Ga 2 P + are studied using the complete active space multi-configuration self-consistent field followed by multi-reference singles + doubles configuration interaction (MRSDCI) computations. Potential energy curves of the low-lying electronic states of these species are determined. Geometries, energy separations of these electronic states and the adiabatic ionization energies of Ga 2 P and GaP 2 are computed.

Electronic states of Ga3P and GaP3 clusters

Abstract Complete active space multi-configuration self-consistent field (CASSCF) followed by multi-reference singles+doubles configuration interaction (MRSDCI) computations are carried out on the low-lying electronic states of Ga 3 P and GaP 3. The ground states of Ga 3 P and GaP 3 are found to be 1 A 1 and 3 A 2 , respectively, with trigonal pyramid geometries (C 3v ). Other low-lying excited electronic states of Ga 3 P and GaP 3 are computed. Dipole-allowed transitions in the 2.56 and 1.07 eV regions are predicted for Ga 3 P and GaP 3 , respectively. The relative stability of small clusters Ga x P y ( x + y =3–5) is discussed.

Electronic states of Ga2P2

Abstract Geometries and energy separations of sixteen electronic states of the Ga 2 P 2 cluster are computed using the complete active space multi-configuration self-consistent field followed by multi-reference singles + doubles configuration interaction (MRSDCI) computations that included over a million configurations. The ground state of Ga 2 P 2 was found to be a 1 A g state with an equilibrium structure of a rhombus. Low-lying 3 A u , 1 A u , and 3 B 2g excited states are also found with the same geometries. In addition, several other excited states are obtained.

The electronic states of Ga3

Abstract Complete active space MC SCF (CAS SCF) followed by configuration interaction calculations which employ relativistic effective potentials are carried out on seven low-lying electronic states of Ga 3 and two electronic states of Ga 3 + . The 2 A 1 state is the ground state with a near-equilateral triangular geometry. Two degenerate excited electronic states ( 4 A 2 and 2 B 1 ) are found for Ga 3 with isosceles triangular geometry. The ground state of Ga 3 + is a 1 A 1 closed shell state with a linear geometry.

Potential energy surfaces of electronic states of AlP2, Al2P and their ions

Abstract The low-lying electronic states of AlP 2 , Al 2 P and their anions and cations are investigated using a complete active space multi-configuration self-consistent field technique followed by multi-reference singles+doubles configuration interaction (MRSDCI) calculations. Potential energy surfaces, geometries, energy separations, adiabatic ionization energies, electron affinities, dipole moments vibrational frequencies, zero-point and dissociation energies are computed. While AlP 2 exhibits similarity to the heavier analogs, Al 2 P was found to exhibit a different ground state compared to Ga 2 P and In 2 P.