Alex Brown

Alex Brown
University of Alberta | UAlberta · Department of Chemistry

38.73
 · 
PhD, University of Western Ont
About
118
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2,126
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Introduction
Alex Brown currently works at the Department of Chemistry, University of Alberta. Alex does research in Photochemistry, Spectroscopy, Main Group Chemistry, and Theoretical Chemistry.
Research Experience
Jul 2003
Oct 2002 - Jun 2003
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Research
Research items (118)
Article
The nuclear quadrupole moment of aluminum (²⁷Al) has been re-evaluated by determining the electric field gradients at this nucleus for AlF and AlCl using the coupled cluster method with single, double, and perturbative triple excitations [CCSD(T)]/aug-cc-pwCVXZ (X = T and Q) accounting for both vibrational averaging and core–core/core–valence elect...
Article
In this work, we present a computational study on the antioxidant potential of myricetin 3-O-α-L-rhamnopyranoside (Compound M3) and myricetin 4′-O-α-L-rhamnopyranoside (Compound M4′). Structural parameters, bond dissociation enthalpies (BDEs), ionization potentials (IPs), proton dissociation enthalpies (PDEs), proton affinities (PAs), and electron...
Article
Application of fluorescent proteins (FPs), e.g., as probes for biological imaging, has led to the goal of finding FPs with notable one- and two-photon absorption, OPA and TPA, respectively, features. The variables that affect the TPA cross-section are many, e.g., structurally speaking, some studies have shown its magnitude is influenced by the pres...
Article
The organotin precursors 6‐Br‐Ace‐5‐SnBu3 (6, Ace = acenaphthyl) and 6‐Ph2E‐Ace‐5‐SnBu3 (7a: E = P; 7b: E = As; 7c: E = Sb) were prepared and used for the synthesis of organogold complexes, namely, the homodinuclear arylgold(I) species (6‐Ph2E‐Ace‐5‐Au)2 (8a: E = P; 8b: E = As; 8c: E = Sb), arylgold(III) dichloride 6‐Ph2P‐Ace‐5‐AuCl2 (9), diarylgol...
Article
The synthesis of the first bismuth‐containing macromolecules that exhibit phosphorescence in the solid state and in the presence of oxygen is reported. These red emissive high molecular weight polymers (> 300 kDa) feature benzobismoles appended to a hydrocarbon scaffold, and were built via an efficient ring‐opening metathesis (ROMP) protocol. Moreo...
Article
The synthesis of the first bismuth‐containing macromolecules that exhibit phosphorescence in the solid state and in the presence of oxygen is reported. These red emissive high molecular weight polymers (> 300 kDa) feature benzobismoles appended to a hydrocarbon scaffold, and were built via an efficient ring‐opening metathesis (ROMP) protocol. Moreo...
Article
Non-invasive molecular imaging techniques are accruing more interest in the last decades. Several radiolabelling elements have been FDA-approved and are currently used to characterize tumors. In this study, the DNA intercalating agent doxorubicin was radiolabelled with ¹²⁵I. Several parameters for the radiolabelling reaction were investigated and o...
Article
Full-text available
In this work, we present a computational study on the antioxidant potential of myricetin 3,4\(^{\prime }\)-di-O-α-L-rhamnopyranoside (Compound M). A density functional theory (DFT) approach with the B3LYP and LC-ωPBE functionals and with both the 6-311G(d,p) and 6-311+G(d,p) basis sets was used. The focus of the investigation was on the structural...
Article
Molecular dynamic (MD) simulations were carried out to obtain the conformational changes of the chromophore in the gold fluorescent protein (PDB ID: 1OXF). To obtain two-photon absorption (TPA) cross-sections, time dependent density functional theory (TD-DFT) computations were performed for chromophore geometries sampled along the trajectory. The T...
Article
The structures and energetics of two dihydrochalcones (phloretin and its glycoside phlorizin) were examined with density functional theory, using the B3LYP, M06-2X, and LC-ω PBE functionals with both the 6-311G(d,p) and 6-311 + G(d,p) basis sets. Properties connected to antioxidant activity, i.e., bond dissociation enthalpies (BDEs) for OH groups a...
Article
Full-text available
A well-defined Ir-allyl complex catalyzes the Z-selective cross-coupling of allyl carbonates with α-aryl diazo esters. The process overrides the large thermodynamic preference for E-products typically observed in metal-mediated coupling reactions to enable the synthesis of Z,E-dieneoates in good yield with selectivities consistently approaching or...
Article
Previous research in our group showed that tellurophenes with pinacolboronate (BPin) units at the 2- and/or 5-positions displayed efficient phosphorescence in the solid state, both in the presence of oxygen and water. In this current study, we show that lumi-nescence from a tellurophene is possible when various aryl-based substituents are present,...
Article
The minimum energy structures, i.e., trans-HONO, cis-HONO, HNO2, and OH + NO, as well as the corresponding transition states, i.e., TStrans↔cis, TS1,2H−shift, and TS1,3H−shift, on the ground state potential energy surface (PES) of HONO have been characterized at the CCSD(T)-F12/cc-pVTZ- F12 level of theory. Using the same level of theory, a six-dim...
Article
In this paper, the use of the neural network (NN) method with exponential neurons for directly fitting ab initio data to generate potential energy surfaces (PESs) in sum-of-product form will be discussed. The utility of the approach will be highlighted using fits of CS2, HFCO, and HONO ground state PESs based upon high-level ab initio data. Using a...
Article
Front Cover: The morphological, crystalline, and optoelectronic responses of the polymer PBST3HT, a novel triple-chalcogenophene polymer, enable control of the crystalline structure and optical bandgap. Thermal annealing assists shifts between polymer phases, tuning the bandgap and involving a color change of the homogeneous polymer films. Further...
Article
The authors study adjustable bandgap properties of the novel triple chalcogenophene-based polymer poly-(3-hexyl-2(3-(4-hexylthiophene-2-yl)-4,5-butylselenophene-1-yl)-5-(4,5-butyltellurophene-1-yl)thiophene) through a combination of morphological, spectroscopic, and computational techniques. The bandgap can be tuned after polymerization by means of...
Chapter
Two-photon absorption (TPA) leads to higher-energy excited electronic states via the simultaneous absorption of two photons. In TPA, the absorption is directly proportional to the square of incident light intensity, and thus lasers are required for excitation. The advantages of TPA microscopy include better focus and less out-of-focus bleaching, to...
Article
The effects of explicit hydrogen bonding with H2O on the resonance Raman spectra of uracil and thymine are examined computationally. The three bonding sites in uracil and thymine that form the lowest energy uracil-H2O and thymine-H2O complexes, as well as a more limited number of low-lying ones containing two waters, are considered. The ground stat...
Article
In this article our attempts to tune the color of luminescence within a new class of aggregation-induced emission (AIE) active tellurophenes is reported along with computational details that include spin-orbit coupling effects so as to better understand the nature of emission in the phosphorescent tellurophene (B-Te-6-B). Despite not meeting some o...
Article
The tetrameric red fluorescent protein from Discosoma sp. coral (DsRed) has previously been engineered to produce dimeric and monomeric fluorescent variants with excitation and emission profiles that span the visible spectrum. The brightest of the effectively monomeric DsRed variants is tdTomato - a tandem fusion of a dimeric DsRed variant. Here we...
Article
Two-photon spectroscopy of fluorescent proteins is a powerful bio-imaging tool known for deep tissue penetration and little cellular damage. Being less sensitive than the one-photon microscopy alternatives, a protein with a large two-photon absorption (TPA) cross-section is needed. Here, we use time-dependent density functional theory (TD-DFT) at t...
Article
The HBrO2 isomers have been analyzed computationally to confirm the previous experimental assignments for HOOBr and HOBrO and to assist in future identification of the as yet unobserved HBr(O)O isomer. Optimized geometries of the HOOBr, HOBrO, and HBr(O)O isomers and the transition states connecting them were obtained at the CCSD(T)/O, H: aug-cc-pV...
Article
We have constructed a (semi)-global six-dimensional potential energy surface (PES) for HFCO, incorporating the equilibrium, cis- and trans-isomers (HOCF) as well as the transition states connecting them. The PES is based on a fit to 15000 CCSD(T)-F12/cc-pVTZ-F12 ab initio energies. The sum-of-products PES, obtained using neural network exponential...
Article
A six-dimensional potential energy surface (PES) for formyl fluoride (HFCO) is fit in a sum-of-products form using neural network exponential fitting functions. The ab initio data upon which the fit is based were computed at the explicitly correlated coupled cluster with single, double, and perturbative triple excitations [CCSD(T)-F12]/cc-pVTZ-F12...
Article
We present a computational study on two flavonols that were recently isolated from Loranthaceae family plant extracts: kaempferol 3-O-α-L-arabinofuranosyl-(1 → 3)-α-L-rhamnoside and quercetin 3-O-α-L-arabinofuranosyl-(1 → 3)-α-L-rhamnoside. Their structures and energetics have been investigated at the density functional level of theory, up to B3LYP...
Article
A series of 11 different BODIPY dimers is carefully examined by means of ab initio and TDA-DFT methods. Vertical and 0--0 excitation energies along with the tetra-radical character of these dimers are determined. Possible application of a series of linked dimers for photodynamic therapy (PDT) was investigated through computing their excitation ener...
Chapter
Two-photon absorption (TPA) leads to higher-energy excited electronic states via the simultaneous absorption of two photons. In TPA, the absorption is directly proportional to the square of incident light intensity, and thus lasers are required for excitation. The advantages of TPA microscopy include better focus and less out-of-focus bleaching, to...
Data
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and...
Data
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and...
Data
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and...
Article
Full-text available
Two-photon spectroscopy of fluorescent proteins is a powerful bio-imaging tool characterized by deep tissue penetration and little damage. However, two-photon spectroscopy has lower sensitivity than one-photon microscopy alternatives and hence a protein with a large two-photon absorption cross-section is needed. We use time-dependent density functi...
Article
Full-text available
The stability of a variety of linear and cyclic (BN)n (n = 1–3) adducts with N-heterocyclic carbene (ImMe2; ImMe2 = [(HCNMe)2C:]), N-heterocyclic olefin (ImMe2CH2) and Wittig (Me3PCH2) donors has been examined using M05-2X/cc-pVTZ computations. The strength and nature of the bonds have been investigated using natural bond orbital (NBO) and atoms-in...
Article
The vertical excitation energies of 17 boron–dipyrromethene (BODIPY) core structures with a variety of substituents and ring sizes are benchmarked using time-dependent density functional theory (TD-DFT) with nine different functionals combined with the cc-pVTZ basis set. When compared to experimental measurements, all functionals provide mean absol...
Article
The resonance Raman spectra of the 5-halogenated (F, Cl, and Br) uracils are simulated via the Herzberg-Teller (HT) short-time dynamics formalism. The gradient of the S1 excited state is computed at the CAMB3LYP/aug-cc-pVTZ level of theory in the conductor-like Polarizable Continuum Model for water (C-PCM, H2O), based on the equilibrium geometry de...
Article
We present a computational study on HIO2 molecules. Ground state properties such as equilibrium structures, relative energetics, vibrational frequencies, and infrared intensities were obtained for all the isomers at the coupled-cluster with single and double excitations as well as perturbative inclusion of triples (CCSD(T)) level of theory with the...
Chapter
A brief introduction to quantum computing is provided and the potential use of molecules as the platform is discussed. The basic building blocks (quantum bits, quantum gates, and quantum algorithms) are described in order to emphasize the requirements for realizing a quantum computer, and, the advantages quantum computation has over its classical c...
Article
The zirconium-mediated syntheses of pinacolboronate (BPin) appended benzo[b]tellurophenes and two phenyl/BPin substituted tellurophene isomers with different colors of emission have been achieved. These species are new additions to an emerging class of inorganic heterocycles that display visible phosphorescence in the solid state under ambient cond...
Article
We present isolable examples of formal zinc hydride cations supported by N-heterocyclic carbene (NHC) donors, and investigate the dual electrophilic and nucleophilic (hydridic) character of the encapsulated [ZnH]+ units by computational methods and preliminary hydrosilylation catalysis. A positive approach: Isolable examples of formal zinc hydride...
Article
Two-photon spectroscopy of fluorescent proteins is a powerful bioimaging tool. Considerable effort has been made to measure absolute two-photon absorption (TPA) for the available fluorescent proteins. Being a technically involved procedure, there is significant variation in the published experimental measurements even for the same protein. In this...
Article
The resonance Raman spectrum of uracil is simulated using the Herzberg-Teller short-time dynamics formalism. The ground state geometry is optimized at the levels of PBE0/aug-cc-pVTZ and B3LYP/aug-cc-pVTZ, respectively. The gradient of the bright excited state is computed using Time Dependent Density Functional Theory (TD-DFT) and Spin Flip Time Dep...
Article
The synthesis of the first examples of tellurophenes exhibiting phosphorescence in the solid state and under ambient conditions (room temperature and in air) is reported. Each of these main-group-element-based emitters feature pinacolboronates (BPin) as ring-appended side groups. The nature of the luminescence observed was also investigated using c...
Article
The stability of a variety of borane (BH3 and BH2NHMe) and silane (SiHnPh4–n, n = 0–4) adducts with diamino (NHC) and aminoalkyl (CAAC) carbenes has been carefully examined using M06-2X/cc-pVDZ computations, including natural bond orbital and atoms-in-molecules analyses. Moreover a potential mechanism for the hydride-mediated ring expansion of the...
Article
The nuclear quadrupole coupling and spin-rotation constants of aluminum in AlH and AlD have been determined using coupled cluster theory with single and double excitations as well as perturbative inclusion of triples [CCSD(T)] combined with large correlation-consistent basis sets, cc-pCVXZ (X = T, Q and 5) and aug-cc-pCVXZ (X = T, Q). The anharmoni...
Article
To branch or not to branch: A mild stepwise route to various linear and branched (GeCl2 )x oligogermylenes supported by Lewis bases is reported, including the carbene-bound Ge4 complex NHC⋅GeCl2 Ge(GeCl3 )2 . Dipp=2,6-iPr2 C6 H3 , NHC=N-heterocyclic carbene.
Article
The elusive parent inorganic ethylene H2GeGeH2 has been isolated in the form of a stable complex for the first time via donor–acceptor coordination with suitable Lewis base/acid combinations (LB·H2Ge-GeH2·LA; LB = N-heterocyclic carbene or N-heterocyclic olefin; LA = W(CO)5). The nature of the bonding in these species was investigated by density fu...
Article
In this work, we present time dependent density functional theory (TD-DFT) computations of the photophysical properties for a recently synthesized family of emissive RNA nucleobases (see: D. Shin, R.W. Sinkeldam, Y. Tor, Journal of the American Chemical Society 133 (2011) 14912–14915). These modified analogues are obtained by replacing the imidazol...
Article
The ground state potential energy and dipole moment surfaces for CS$_{2}$ have been determined at the CASPT2/C:cc-pVTZ, S:aug-cc-pV(T+d)Z level of theory. The potential energy surface has been fit to a sum-of-products form using the neural network method with exponential neurons. A generic interface between neural network potential energy surface f...
Article
Full-text available
The photodissociation of vibrationally excited Cl(2)(v = 1) has been investigated experimentally using the velocity mapped ion imaging technique. The experimental measurements presented here are compared with the results of time-dependent wavepacket calculations performed on a set of ab initio potential energy curves. The high level calculations al...
Article
Full-text available
The effect of varying parameters specific to laser pulse shaping instruments on resulting fidelities for the ACNOT(1), NOT(2), and Hadamard(2) quantum logic gates are studied for the diatomic molecule (12)C(16)O. These parameters include varying the frequency resolution, adjusting the number of frequency components and also varying the amplitude an...
Article
The nuclear quadrupole coupling constants (NQCCs) for the nitrogen and oxygen nuclei in N(2)O have been determined using a variety of computational methods (MP2, QCISD, DFT with B3LYP, PBE0, and B3PW91 functionals, CCSD, CCSD(T), CASSCF, and MRCI) combined with correlation-consistent basis sets. When compared to the available experimental determina...
Article
Full-text available
A fully quantum mechanical dynamical calculation on the photodissociation of molecular chlorine is presented. The magnitudes and phases of all the relevant photofragment T-matrices have been calculated, making this study the computational equivalent of a "complete experiment," where all the possible parameters defining an experiment have been deter...
Article
Full-text available
Velocity mapped ion imaging and resonantly enhanced multiphoton ionization time-of-flight methods have been used to investigate the photodissociation dynamics of the diatomic molecule Cl(2) following excitation to the first UV absorption band. The experimental results presented here are compared with high level time dependent wavepacket calculation...
Article
Deuterium kinetic isotope effects (KIEs) are reported for the first time for the dissociation of a protein-ligand complex in the gas phase. Temperature-dependent rate constants were measured for the loss of neutral ligand from the deprotonated ions of the 1:1 complex of bovine β-lactoglobulin (Lg) and palmitic acid (PA), (Lg + PA)(n-) → Lg(n-) + PA...
Article
General chemical strategies which provide controlled changes in the emission or absorption properties of biologically compatible fluorophores remain elusive. One strategy employed is the conversion of a fluorophore-attached alkyne (or azide) to a triazole through a copper-catalyzed azide-alkyne coupling (CuAAC) reaction. In this study, we have comp...
Article
Full-text available
The importance of the ro-vibrational state energies on the ability to produce high fidelity binary shaped laser pulses for quantum logic gates is investigated. The single frequency 2-qubit ACNOT(1) and double frequency 2-qubit NOT(2) quantum gates are used as test cases to examine this behaviour. A range of diatomics is sampled. The laser pulses ar...
Article
Full-text available
We have demonstrated the use of ab initio molecular dynamics (AIMD) trajectories to compute the vibrational energy levels of molecular systems in the context of the semiclassical initial value representation (SC-IVR). A relatively low level of electronic structure theory (HF/3-21G) was used in this proof-of-principle study. Formaldehyde was used as...
Article
Full-text available
Frequency domain shaped binary laser pulses were optimized to perform 2 qubit quantum gate operations in (12)C(16)O. The qubit rovibrational state representation was chosen so that all gate operations consisted of one-photon transitions. The amplitude and phase varied binary pulses were determined using a genetic algorithm optimization routine. Bin...
Article
Full-text available
We present a modified version of a previously published algorithm (Gollub et al 2008 Phys. Rev. Lett.101 073002) for obtaining an optimized laser field with more general restrictions on the search space of the optimal field. The modification leads to enforcement of the constraints on the optimal field while maintaining good convergence behaviour in...
Article
A scheme for coherent population transfer via four quantum states in atomic or molecular systems of high-energy transitions by induced multiphoton adiabatic passage (IMAP) is proposed. The nonperturbative multiphoton resonant theory of interaction of such quantum systems with the two strong laser fields of different frequencies is developed and the...
Article
The photophysical properties of fluorochromes are directly influenced by their chemical structure. There is increasing interest in chemical strategies that provide controlled changes to the emission properties of biologically compatible fluorophores. One strategy employed is the conversion of a fluorophore-attached alkyne to a triazole through a co...
Article
Full-text available
Comparative studies of implementations of the controlled NOT quantum gate operation using vibrational states of ammonia as the qubit states are presented. The quantum gate operations are realized using tailored laser pulses, which are calculated using a combined approach of optimal control theory and the multiconfiguration time-dependent Hartree me...
Article
The ground (X(1)A ') and two lowest lying excited singlet states (1(1)A '' and 2(1)A ') of methyl hypochlorite have been examined using ab initio electronic structure techniques to validate computationally efficient methods, upon which direct dynamics can be based, versus high-level ones, for which direct dynamics would be intractable. Ground-state...
Chapter
Introduction Optimal Control Theory Methods for Solving the Optimal Control Problem The Electric Nuclear Born-oppenheimer Approximation Solution of Time-Dependent Schrödinger Equation Analytic Design of Optimal Laser Pulses Summary Appendix A: Variation of The Objective Functional and Derivation of the Optimal Control Equations Appendix B: Optimal...
Article
We have extended a previously implemented algorithm for using optimal control theory within the multi-configurational time-dependent Hartree (MCTDH) software. The new implementation allows the use of arbitrary dipole operators for generating the optimal laser field. A variant that does not require saving the time-dependent wave function has been de...
Article
By virtue of its self-sufficiency to form a visible wavelength chromophore within the confines of its tertiary structure, the Aequorea victoria green fluorescent protein (GFP) is single-handedly responsible for the ever-growing popularity of fluorescence imaging of recombinant fusion proteins in biological research. Engineered variants of GFP with...
Article
The effects of permanent dipole moments on stimulated Raman adiabatic passage (STIRAP) are considered. Analytic expressions for the Hamiltonian including the effects of permanent dipole moments are developed for the STIRAP process. The potential detrimental effect of permanent dipoles on population transfer using standard STIRAP techniques is demon...
Article
The assumption that the photodissociation of HI proceeds adiabatically is re-examined in the context of recently calculated alignment parameters, a(⟂), for the ground state halogen atoms resulting from photodissociation of the analogous HCl and HBr molecules. The a(⟂) alignment parameters for HCl, HBr, and HI are determined from time-dependent quan...
Article
The effects of a background state, or states, on stimulated Raman adiabatic passage (STIRAP) processes are investigated. The study is based on a realistic model of the laser-assisted HCN→HNC isomerization process. While the high density of states in the energy regime above the isomerization barrier plays an important role, the strong variation of t...
Article
Full-text available
In this paper, a new method is proposed to design optimized control fields with desired temporal and/or spectral properties. The method is based on penalizing the difference between an optimized field obtained from an iterative scheme and a reference field with desired temporal and/or spectral properties. Compared with the standard optimal control...
Article
Ab initio potential energy curves, transition dipole moments, and spin-orbit coupling matrix elements are computed for HBr. These are then used, within the framework of time-dependent quantum-mechanical wave-packet calculations, to study the photodissociation dynamics of the molecule. Total and partial integral cross sections, the branching fractio...
Chapter
The theory of time-dependent wavepaeket calculations of reactive scattering and photodissociation is briefly reviewed and some illustrative results presented. Particular attention will be paid to the theory of differential scattering cross sections, arising from both types of process, and to the symmetry of angular dependent scattering in a photodi...
Article
Full-text available
In a recent paper [D. Babikov, J. Chem. Phys. 121, 7577 (2004)], quantum optimal control theory was applied to analyze the accuracy of quantum gates in a quantum computer based on molecular vibrational eigenstates. The effects of the anharmonicity parameter of the molecule, the target time of the pulse, and the penalty function on the accuracy of t...
Article
Full-text available
Amplitudes and phases of the photofragmentation T matrix can be determined from experiment by measuring the vector correlation coefficients of the photofragments. Comparison of the experimentally obtained data with the results of quantum mechanical calculation allows the realization of the complete experiment in the field of molecular photodynamics...
Article
Full-text available
The photodissociation dynamics of HI and DI are examined using time-dependent wave-packet techniques. The orientation and alignment parameters aQ(K) (p) are determined as a function of photolysis energy for the resulting ground-state I(2P(3/2)) and excited-state I(2P(1/2)) atoms. The aQ(K) (p) parameters describe the coherent and incoherent contrib...
Article
Full-text available
The complete angular momentum distributions and vector correlation coefficients (orientation and alignment) of ground state I((2)P(32)) and excited state I((2)P(12)) atoms resulting from the photodissociation of HI have been computed as a function of photolysis energy. The orientation and alignment parameters a(Q) ((K))(p) that describe the coheren...
Article
Full-text available
Adiabatic potential energy surfaces for the six lowest singlet electronic states of N(2)O (X (1)A('), 2 (1)A('), 3 (1)A('), 1 (1)A("), 2 (1)A(") and 3 (1)A(")) have been computed using an ab initio multireference configuration interaction (MRCI) method and a large orbital basis set (aug-cc-pVQZ). The potential energy surfaces display several symmet...
Chapter
Driven MD offers a simple classical scheme for extracting the vibrational normal modes without an explicit knowledge of the second derivative matrix, the Hessian. The standard setup and diagonalization of the Hessian is replaced by a resonant excitation of the molecule (at a frequency ω) using a sinusoidal time-dependent perturbation. To solve the...
Article
The interaction of a two-level dipolar molecule with two laser pulses, where one laser’s frequency is tuned to the energy level separation (pump laser) while the second laser’s frequency is extremely small (probe laser), is investigated. A dipolar molecule is one with a nonzero difference between the permanent dipole moments of the molecular states...
Article
Full-text available
The driven molecular-dynamics (DMD) method, recently proposed by Bowman, Zhang, and Brown [J. Chem. Phys. 119, 646 (2003)], has been implemented into the TINKER molecular modeling program package. The DMD method yields frequencies and normal modes without evaluation of the Hessian matrix. It employs an external harmonic driving term that can be use...