Michael Robb
Email: mike.robb@imperial.ac.uk Professor and Chair of Chemistry, Imperial College, London (U.K.) Contributions to Gaussian: CASSCF Methods Research InterestsDr. Robb's current research includes both methods development and applications studies, focusing on Multi-Configuration SCF methods (MC-SCF), which is also known as the Complete Active Space SCF (CASSCF) method. These calculations combine an SCF calculation with a full Configuration Interaction computation involving a subset of the molecular orbitals known as the active space. The CASSCF method has many uses and is especially suited to the study of excited states. CASSCF code developed by Dr. Robb and his colleagues first appeared in Gaussian 90. They enhanced Gaussian 92's CASSCF capabilities to include coupled perturbed CASSCF as well as a direct CASSCF algorithm. Gaussian 94 again brought significantly enhanced CASSCF facilities, including the following new capabilities and features:
Dr. Robb's applications research centers on theoretical studies of organic reaction mechanisms. Along with his own group, his colleagues from the University of Bologna, Fernando Bernardi and Massimo Olivucci, and their research groups, Dr. Robb has investigated a wide variety of problems. Recent work includes many studies of the reaction paths for organic photochemical reactions, including the discovery of a novel conical intersection mechanism for photochemical [2+2] cycloadditions. Previously, the mechanism for such radiationless-decay reactions was assumed to occur via an avoided crossing; Dr. Robb and his collaborators demonstrated that it actually occurs via a conical intersection (surface crossing), which is a point shared in common between the ground and excited state potential energy surfaces. Following on this work, Dr. Robb and his coworkers have documented a new mechanistic approach to organic photochemistry through the study of the Born-Oppenheimer violation regions of potential energy surfaces. This initial breakthrough has led to a substantial number of impressive new results, including new mechanisms for photochemical [2+2] cycloadditions, the photochemical ring opening of cyclobutenes, photochemical sigmatropic rearrangements, the photochemical transformation of ergosterol and hexatrienes, the photochemical cycloaddition of Dewar benzene, the S1 and S2 photochemical reactions of benzene, the photochemistry of butadiene, the singlet di-p-methane rearrangement, and the Paterno-Buchi reaction. Research into these and related problems is ongoing. Selected PublicationsBlancafort L, Celani P, Bearpark MJ, Robb MA, "A valence-bond-based complete-active-space self-consistent-field method for the evaluation of bonding in organic molecules", Theor. Chem. Acc. 110, (2003), 92-99. Garavelli M, Ruggeri F, Ogliaro F, Bearpark MJ, Bernardi F, Olivucci M, Robb MA "A simple approach for improving the hybrid MMVB force field: Application to the photoisomerization of s-cis butadiene", J. Comp. Chem. 24, (2003), 1357-1363. Klene M, Robb MA, Blancafort L, Frisch MJ "A new efficient approach to the direct restricted active space self-consistent field method", J. Chem. Phys. 119, (2003), 713-728. Worth GA, Hunt P, Robb MA "Nonadiabatic dynamics: A comparison of surface hopping direct dynamics with quantum wavepacket calculations", J. Phys. Chem. A 107, (2003), 621-631. Boggio-Pasqua M, Ravaglia M, Bearpark MJ, Garavelli M, Robb MA "Can diarylethene photochromism be explained by a reaction path alone? A CASSCF study with model MMVB dynamics", J. Phys. Chem. A 107, (2003), 11139-11152. Bearpark MJ, Boggio-Pasqua M "Excited states of conjugated hydrocarbon radicals using the molecular mechanics - valence bond (MMVB) metho", Theor. Chem. Acc. 110, (2003), 105-114. Afarinkia K, Bearpark MJ, Ndibwami A "Computational and experimental investigation of the Diels-Alder cycloadditions of 4-chloro-2(H)-pyran-2-one", J. Org. Chem. 68, (2003), 7158-7166. Paterson MJ, Hunt PA, Robb MA, Takahashi O "Non-adiabatic direct dynamics study of chromium hexacarbonyl photodissociation", J. Phys. Chem. A 106, (2002), 10494-10504. Jolibois F, Bearpark MJ, Robb MA "Potential energy surfaces and dynamical behavior of two rigidly linked bichromophoric molecules studied by CASSCF computations and ab initio classical trajectory simulations", J. Phys. Chem. A 106, (2002), 4358-4367. Boggio-Pasqua M, Bearpark MJ, Hunt PA, Robb MA "Dihydroazulene/vinylheptafulvene photochromism: A model for one-way photochemistry via a conical intersection", J. Am. Chem. Soc. 124, (2002), 1456-1470. Deumal M, Bearpark MJ, Novoa JJ, Robb MA "Magnetic properties of organic molecular crystals via an algebraic Heisenberg Hamiltonian. Applications to WILVIW, TOLKEK, and KAXHAS nitronyl nitroxide crystals", J. Phys. Chem. A 106, (2002), 1299-1315. Worth GA, Robb MA "Applying direct molecular dynamics to non-adiabatic systems", Adv. Chem. Phys. 124, (2002), 355-431.
Last update: 23 September 2011 |
