Proximity algorithm for solving a pulse transmission cross-section

摘要

Method for determining a molecular structure of an analyte comprising:Determination of a two-dimensional ion mobility and mass spectrum of an unknown analyte using a combined ion mobility and mass spectrometer;Calculate a molecular pulse transmission cross-section in a drift tube of the combined ion mobility and mass spectrometer based on the two-dimensional ion mobility and mass spectrum of the unknown analyte, wherein the drift tube is filled with a buffer gas;Calculate a molecular pulse transmission cross-section for each of a plurality of known compounds according to the following steps:Calculate a function of potential energy, wherein the function of potential energy describes an interaction potential between a molecular analysis and a buffer gas particle at position r according to the following equation:whereis substantially identical to a (standard) Lennard-Jones 12,6 potential, andis identical to the (standard) potential of charge-induced interaction with polarizability α;Calculate a function of pulse transmission using the function of potential energy, wherein the function of pulse transmission includes a probability that a collision at the positionat a kinetic energy η occurs according to the following equationCalculating a pulse transmission surfaceusing the function of pulse transmission, wherein the pulse transmission surface is a set of pointsis where a collision according to the Monte Carlo criterionis predicted to occur, where p is a random number andis the function of pulse transmission;Calculate the molecular pulse transmission cross-section for each of the known compounds using the pulse transmission function and the pulse transmission surface, wherein the molecular pulse transmission cross-section comprises an effective area of analysis, when an impulse is transmitted between the analysis and the buffer gas at temperature T due to a collision occurring in a drift cell in the combined immobility and mass spectrometer according to the following equation:where f(e,T) is the molecular Boltzmann factor described above,is the alignment-centred cross-section; andis the form factor for kinetic energy; andComparing the molecular pulse transmission cross-section of the unknown analyte with the molecular pulse transmission cross-section of the plurality of known compounds and indicating a possible identity of the unknown analyte by matching the compared molecular pulse transmission cross-sections.