Publications

@article{Ramaswamy1980,
title = {Semiclassical quantization of multidimensional systems},
author = {R Ramaswamy, P Siders and R A Marcus
},
url = {https://doi.org/10.1063/1.439939},
doi = {10.1063/1.439939},
issn = {0021-9606},
year = {1980},
date = {1980-11-15},
journal = {The Journal of Chemical Physics},
volume = {73},
number = {10},
pages = {5400–5401},
abstract = {Low order classical perturbation theory is used to obtain semiclassical eigenvalues for a system of three anharmonically coupled oscillators. The results in the low energy region studied here agree well with the ’’exact’’ quantum values. The latter had been calculated by matrix diagonalization using a large basis set.},
keywords = {Coupled Oscillators, Perturbation},
pubstate = {published},
tppubtype = {article}
}

@article{Ramaswamy1980z,
title = {Dynamics of van der Waals molecules: A scaling theoretical analysis of I2*He},
author = {Ramakrishna Ramaswamy and Andrew E DePristo},
url = {https://ramramaswamy.org/papers/010.pdf},
doi = {10.1063/1.438915},
year = {1980},
date = {1980-01-01},
journal = {J. Chem. Phys.},
volume = {72},
number = {1},
pages = {770},
keywords = {molecular dynamics, scaling},
pubstate = {published},
tppubtype = {article}
}

@article{DePristo1979,
title = {Quantum number and energy scaling for non-reactive collisions},
author = {A E DePristo, S D Augustin, R Ramaswamy and H Rabitz
},
url = {https://doi.org/10.1063/1.438376},
doi = {10.1063/1.438376},
issn = {0021-9606},
year = {1979},
date = {1979-07-15},
journal = {The Journal of Chemical Physics},
volume = {71},
number = {2},
pages = {850-865},
abstract = {Two new theoretical developments are presented in this article. First an energy corrected sudden (ECS) approximation is derived by explicitly incorporating both the internal energy level spacing and the finite collision duration into the sudden S‐matrix. An application of this ECS approximation to the calculation of rotationally inelastic cross sections is shown to yield accurate results for the H+–CN system. Second, a quantum number and energy scaling relationship for nonreactive S‐matrix elements is derived based on the ECS method. A few detailed illustrations are presented and scaling predictions are compared to exact results for R–T, V–T, and V–R, T processes in various atom–molecule systems. The agreement is uniformly very good — even when the sudden approximation is inaccurate. An important result occurs in the analysis of V–T processes: the effects of anharmonic wave functions (coupling) and decreasing vibrational energy gaps (energetics) are separated. Each factor makes significant contributions to the deviation of the anharmonic from the harmonic scaling relationship.},
keywords = {Scattering},
pubstate = {published},
tppubtype = {article}
}

@article{Ramaswamy1979,
title = {Stochastic theory of collisions: Application to vibration–rotation inelasticity in CO–He},
author = {R Ramaswamy, S Augustin and H Rabitz},
url = {https://doi.org/10.1063/1.437706},
doi = {10.1063/1.437706},
issn = {0021-9606},
year = {1979},
date = {1979-03-01},
journal = {The Journal of Chemical Physics},
volume = {70},
number = {5},
pages = {2455–2462},
abstract = {Vibration–rotation inelasticity in the CO–He collision system is studied within the stochastic formulation. Cross sections are obtained for purely rotational transitions using a modified electron gas potential. Vibration–rotation cross sections have been calculated in the energy range 2200 cm−1 keywords = {molecular dynamics, Stochasticity},
pubstate = {published},
tppubtype = {article}
}

@article{Ramaswamy1979z,
title = {On the correlation of rotationally inelastic rates: A scaling theoretical analysis},
author = {R Ramaswamy and A E Z Depristo and H Rabitz},
url = {https://ramramaswamy.org/papers/009.pdf},
year = {1979},
date = {1979-01-01},
journal = {Chem. Phys. Lett.},
volume = {61},
number = {3},
pages = {495–497},
keywords = {Inelasticity, molecular dynamics, scaling},
pubstate = {published},
tppubtype = {article}
}

@article{Ramaswamy1978,
title = {Stochastic theory of intramolecular energy transfer},
author = {R Ramaswamy, S Augustin and H Rabitz},
url = {https://doi.org/10.1063/1.436544},
doi = {10.1063/1.436544},
issn = {0021-9606},
year = {1978},
date = {1978-12-15},
journal = {The Journal of Chemical Physics},
volume = {69},
number = {12},
pages = {5509-5517},
abstract = {The problem of internal energy redistribution in an isolated polyatomic molecule is treated by a stochastic theory approach. The fundamental assumption of this work is that a random phase approximation is valid at specific time intervals. This results in the replacement of the Schrödinger equation by a master equation that governs the evolution of a probability distribution in the quantum levels of the molecule. No assumptions regarding the strength of the coupling are made, and the problem of energy conservation is specifically considered. A stochastic variable is introduced in order to satisfy the requirement that the total energy remain fixed. The further approximation of the master equation by a Fokker–Planck diffusion-like equation is outlined; the latter approach is particularly attractive for treating large molecules. Finally, the master‐equation theory is applied to a model problem representing a linearly constrained triatomic molecule, and the time evolution of an initially localized excitation is discussed.},
keywords = {energy conservation, probability, Stochasticity},
pubstate = {published},
tppubtype = {article}
}

@article{Green1978,
title = {Collisional excitation of interstellar molecules: H2},
author = {S Green, R Ramaswamy and H Rabitz
},
url = {https://ui.adsabs.harvard.edu/abs/1978ApJS…36..483G},
doi = {10.1086/190509},
year = {1978},
date = {1978-04-01},
journal = { Astrophysical Journal Supplement Series},
volume = {36},
pages = {483-496},
abstract = {Cross sections for the important rotational transitions in molecular hydrogen collisions are presented for rotational levels to j = 11 and energies to 20,000 K. These have been obtained from extensive theoretical calculations. The resulting cross sections are fitted to a simple polynomial in the energy, and the coefficients are tabulated for easy utilization.},
keywords = {hydrogen, interstellar gas, molecular dynamics, Scattering},
pubstate = {published},
tppubtype = {article}
}

@article{Ramaswamy1978z,
title = {Rotational inelasticity in high-energy H2-H2 Collisions},
author = {Ramakrishna Ramaswamy Herschel Rabitz and Sheldon Green},
url = {https://ramramaswamy.org/papers/005.pdf},
year = {1978},
date = {1978-01-01},
journal = {Chemical Physics},
volume = {28},
pages = {319-329},
keywords = {Inelasticity, molecular dynamics},
pubstate = {published},
tppubtype = {article}
}

@article{Ramaswamy1977b,
title = {Low-temperature relaxation in gaseous H2 and D2},
author = {Ramakrishna Ramaswamy, Herschel Rabitz, Sheldon Green},
url = {https://doi.org/10.1063/1.434315},
doi = {10.1063/1.434315},
issn = {0021-9606},
year = {1977},
date = {1977-04-01},
journal = {The Journal of Chemical Physics},
volume = {66},
number = {7},
pages = {3021-3030},
abstract = {Various potentials have been used for generating scattering cross sections for rotational transitions in hydrogen isotope systems. Low‐temperature rates were calculated and the relaxation times compared with the results of sound absorption experiments. It is seen that the existing potentials could still be improved since they do not exactly reproduce the experimental results.},
keywords = {isotopes, Scattering},
pubstate = {published},
tppubtype = {article}
}

@article{Ramaswamy1977z,
title = {Electron momentum distributions and compton profiles of some molecules with FSGO model},
author = {S R Gadre R Ramaswamy and P T Narasimhan},
url = {https://ramramaswamy.org/papers/002.pdf},
year = {1977},
date = {1977-01-01},
journal = {Pramana},
volume = {8},
number = {2},
pages = {99–107},
keywords = {molecular dynamics},
pubstate = {published},
tppubtype = {article}
}

@article{Ramaswamy1977,
title = {Vibration-rotation relaxation in bimolecular collisions with application to para-Hydrogen},
author = {R Ramaswamy and H Rabitz},
url = {https://doi.org/10.1063/1.433648},
doi = {10.1063/1.433648},
issn = {0021-9606},
year = {1977},
date = {1977-01-01},
journal = {The Journal of Chemical Physics},
volume = {66},
number = {1},
pages = {152-159},
abstract = {Three‐dimensional quantum mechanical calculations in the effective potential approximation have been made on the para‐hydrogen system. At low temperatures, vib–rotationally inelastic collisions were examined while breathing sphere calculations were used to probe the high‐temperature regime. It was found that simultaneous vibrational and rotational processes contribute to the overall mechanism of vibrational relaxation. Collisionally induced intra‐ and intermolecular energy transfer is possible in the present calculation, and the corresponding cross sections are examined in detail. Rates are calculated from the cross sections and compared with experiment.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{Alexe2017,
title = {Data Perturbation Independent Diagnosis and Validation of Breast Cancer Subtypes Using Clustering and Patterns},
author = {G Alexe and G S Dalgin and R Ramaswamy and C Delisi and G Bhanot},
url = {https://ramramaswamy.org/papers/110.pdf},
doi = {10.1177/117693510600200006},
issn = {1176-9351},
journal = {Cancer Informatics},
volume = {2},
pages = {117693510600200},
abstract = {Molecular stratification of disease based on expression levels of sets of genes can help guide therapeutic decisions if such classifications can be shown to be stable against variations in sample source and data perturbation. Classifications inferred from one set of samples in one lab should be able to consistently stratify a different set of samples in another lab. We present a method for assessing such stability and apply it to the breast cancer (BCA) datasets of Sorlie et al. 2003 and Ma et al. 2003. We find that within the now commonly accepted BCA categories identified by Sorlie et al. Luminal A and Basal are robust, but Luminal B and ERBB2+ are not. In particular, 36% of the samples identified as Luminal B and 55% identified as ERBB2+ cannot be assigned an accurate category because the classification is sensitive to data perturbation. We identify a “core cluster” of samples for each category, and from these we determine “patterns” of gene expression that distinguish the core clusters from each other. We find that the best markers for Luminal A and Basal are (ESR1, LIV1, GATA-3) and (CCNE1, LAD1, KRT5), respectively. Pathways enriched in the patterns regulate apoptosis, tissue remodeling and the immune response. We use a different dataset (Ma et al. 2003) to test the accuracy with which samples can be allocated to the four disease subtypes. We find, as expected, that the classification of samples identified as Luminal A and Basal is robust but classification into the other two subtypes is not.},
keywords = {breast cancer, clusters, diagnosis, multi-gene biomarkers, patterns},
pubstate = {published},
tppubtype = {article}
}

@article{Bhanot,
title = {Robust meta-analysis of genomic data for cancer diagnosis},
author = {Gabriela Bhanot Gyan Alexe and Babu Vengataraghavan and Jorge Lepre and Arnold J Levine and Gustavo Stolovitzky},
url = {https://ramramaswamy.org/papers/R36.pdf},
pages = {7–8},
keywords = {cancer diagnosis, combinatorial biomarkers, meta-analysis, meta-classifiers, patterns},
pubstate = {published},
tppubtype = {article}
}

@article{,
title = {Design strategies for generalized synchronization},
author = { },
url = { },
doi = { },
journal = { },
volume = { },
publisher = {American Physical Society},
abstract = { },
keywords = {Chaos, Coupled Lorenz System, Generalized Synchronization},
pubstate = {published},
tppubtype = {article}
}