Influence of conformational changes in complex molecules on photon statistics of single molecule fluorescence

Journal Article · Wed Jun 15 00:00:00 EDT 2011 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.83.063841· OSTI ID:21550222

Osad'ko, I S ^[1]; Fedyanin, V V ^[2]

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1. Institute of Spectroscopy Russian Academy of Sciences (RAS), 142190 Troitsk, Moscow Region (Russian Federation)
2. Moscow Pedagogical State University, 119991 Moscow (Russian Federation)

A single complex molecule with conformational changes (conformations 0 and 2) is considered. When such a molecule is irradiated by cw-laser light it can randomly change the intensity or polarization of its fluorescence due to jumps from one conformation to another. In fact, the molecule manifests itself either like the 0-type or the 2-type emitter. An expression for the matrix s{sub {alpha}{beta}}(t) called the start-stop correlator (waiting time distribution) in which {alpha}=0,2 and {beta}=0,2 is derived. An expression for the matrix p{sub {alpha}{beta}}(t) called the full correlator is derived as well. It determines the density of the probability of finding an event of {alpha} type and an event of {beta} type separated by time interval t. A relation between matrices s{sub {alpha}{beta}}(t) and p{sub {alpha}{beta}}(t) is found. A mathematical expression for the distribution w{sub N}(T) of events measured in time interval T is derived. It is expressed solely via the matrix s{sub {alpha}{beta}}(t). Numerical calculations of the event distribution function for various rates of intra- and interconformational jumps are carried out with the help of the formula for w{sub N}(T) and by the Monte Carlo method. Both methods of the calculation yield identical distributions. Fluctuating fluorescence intensity I(t) for a bin time of 5 ms is calculated for slow and fast interconformational jumps. A relation is found between the autocorrelation function g{sup (2)}(t) of fluorescence measurable in experiments and the matrix p{sub {alpha}{beta}}(t) calculated theoretically.

• OSTI ID: 21550222
• Journal Information: Physical Review. A, Vol. 83, Issue 6; Other Information: DOI: 10.1103/PhysRevA.83.063841; (c) 2011 American Institute of Physics; ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
74 ATOMIC AND MOLECULAR PHYSICS
CONFORMATIONAL CHANGES
DISTRIBUTION FUNCTIONS
FLUORESCENCE
LASER RADIATION
MATRICES
MOLECULES
MONTE CARLO METHOD
PHOTONS
POLARIZATION
PROBABILITY
STATISTICS
VISIBLE RADIATION
BOSONS
CALCULATION METHODS
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
EMISSION
FUNCTIONS
LUMINESCENCE
MASSLESS PARTICLES
MATHEMATICS
PHOTON EMISSION
RADIATIONS